The making of irregular migration: post-Brexit immigration policy and risk of labour exploitation

Meri ÅhlbergFocus on Labour Exploitation (FLEX), United Kingdom

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Lucila GranadaFocus on Labour Exploitation (FLEX), United Kingdom

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This article highlights the role states have in creating the conditions under which labour exploitation can occur. Specifically, it identifies several immigration policy decisions related to the UK’s exit from the European Union that will likely result in an increase in the number of irregular migrants in the United Kingdom and how this increase, when combined with measures that have progressively restricted the rights and entitlements of various immigration categories, creates an environment conducive to labour exploitation. It presents measures that could help address this problem, including changes to immigration policies and the strengthening of the labour market enforcement system.


This article highlights the role states have in creating the conditions under which labour exploitation can occur. Specifically, it identifies several immigration policy decisions related to the UK’s exit from the European Union that will likely result in an increase in the number of irregular migrants in the United Kingdom and how this increase, when combined with measures that have progressively restricted the rights and entitlements of various immigration categories, creates an environment conducive to labour exploitation. It presents measures that could help address this problem, including changes to immigration policies and the strengthening of the labour market enforcement system.


This article highlights the central role that states have in creating the conditions under which labour exploitation, including forced labour, human trafficking and other offences classed as ‘modern slavery’, are able to occur. Specifically, this article identifies a number of immigration policy decisions related to the UK’s exit (‘Brexit’) from the European Union (EU) that will likely result in a sharp increase in the number of irregular migrants in the United Kingdom (UK) and how this increase, when combined with measures that have progressively restricted the rights and entitlements of various immigration categories, creates an environment conducive to labour exploitation.

There are several ways in which states shape and define the conditions that enable labour exploitation, both directly and indirectly. Yet states are often only considered in terms of their responses to labour exploitation, ‘rather than as actors who play a causal role in shaping the conditions that give rise to it’ (LeBaron and Phillips, 2019: 2). LeBaron and Phillips (2019) identify multiple ways in which the state facilitates what they call ‘unfree labour’ – a term that ‘encompasses exploitative practices often described as forced labour, human trafficking, and “modern slavery”’. Throughout this article we will refer to ‘labour exploitation’, which similarly encompasses internationally criminalised practices that in the UK fall under the Modern Slavery Act 2015, like forced labour and human trafficking, but also refers to the ‘grey area’ that often falls below this criminal threshold, namely ‘work situations that deviate significantly from standard working conditions as defined by legislation or other legal instruments, concerning in particular remuneration, working hours, leave entitlements, health and safety standards and decent treatment’ (FRA, 2019: 10).

Immigration policy is one of the key means through which the state creates conditions for labour exploitation. It does so directly for example by establishing labour migration programmes that remove labour rights and protections, and indirectly through restrictive policies governing cross-border and labour market mobility, as well as access to social protection (LeBaron and Phillips, 2019: 3).

Understanding the ways in which immigration policy can enable and drive labour exploitation is particularly important in the post-Brexit context due to the complete overhaul of the UK’s immigration system that happened as a result of it. Existing immigration routes were replaced by new, more restrictive visa regimes; old restrictions were expanded to new groups of migrants; and EU citizenship rights were replaced with immigration controls (Immigration and Social Security Co-ordination (EU Withdrawal) Act, 2020). These changes have the potential to considerably increase the risk of labour exploitation in the UK. A key factor contributing to this increased risk, and the main focus of this article, is the likely increase in people becoming or being classed as irregular migrants as a result of these immigration policy changes. Irregular migrants – defined in this article as people who are in the UK without a legal right to remain or who are not adhering to their visa conditions – are at heightened risk of experiencing exploitation in the UK due to having fewer employment options and severely restricted employment rights, as well as risking immigration repercussions, including arrest, detention and deportation, if they come to the attention of authorities. Exploitative employers are able to capitalise on the vulnerability of irregular migrants by imposing exploitative conditions and coercing people into work with the knowledge that they are unlikely to complain to or seek help from authorities.

Before this article outlines the Brexit-related factors that could result in a sharp increase in irregular migrant workers, it first follows the expansion of the category over time and interrogates what ‘irregularity’ means and the UK-specific factors that make being irregular particularly high-risk. Irregular migrants are not a homogenous group of people, but a complex and diverse category that covers a number of statuses, something which is crucial to understand in order to effectively analyse the different ways in which immigration policy could increase or reduce irregularity and, as a consequence, risk of exploitation.

Freedom of movement and the creation of irregularity

Immigration controls that restrict who can enter, reside and settle in the UK, for what purposes, and the rights and entitlements they can access, are historically relatively new. The UK has, for most of its history, had some level of free movement of people across its borders, and did not start actively controlling immigration until the start of the twentieth century, with the Aliens Act 1905. This Act was the first piece of legislation to define some groups of migrants as ‘undesirable’, making their entry to the UK discretionary, rather than automatic (Pellew, 1989). Proof of identity when entering the UK was only made mandatory for all in the context of the First World War, under the British Nationality and Status of Aliens Act (Aliens Restriction Act) 1914. The Act, passed to control the entry and residence of ‘enemy aliens’, gave the state the power to prohibit certain foreign nationals from entering the UK, restrict their movement within the UK and deport those seen as a threat to Britain (Girvan, 2018). These wartime powers were extended into peace-time under the Aliens Restriction (Amendment) Act 1919, which for the first time linked immigration controls with the labour market (Pearsall, 2017). Migrants classed as ‘aliens’ were required to seek permission for employment, barred from certain jobs and had their employment rights restricted (Pearsall, 2017). In restricting who could enter the UK, under what conditions and what their rights were once in-country, the Acts introduced in this relatively short period of time also created the possibility of irregular migration.

Though the 1914 Act and subsequent amendment acts introduced immigration controls for some foreigners, a considerable part of the world’s population continued to have freedom of movement without immigration controls with the UK. Citizens of British colonies, for instance, had the same rights and entitlements as someone born in the UK. They were classed first as ‘British Subjects’ and then, with the introduction of the British Nationality Act 1948, as ‘Citizens of the United Kingdom and Colonies’ (Yeo, 2017). As such they had the right to, at least in theory, live and work anywhere within the territories of the UK and Colonies. This freedom of movement, which also extended to all citizens of the Commonwealth, enabled British businesses and employers, including the National Health Service (NHS), to recruit workers from other countries when needed, such as to support reconstruction and economic growth after the Second World War (Yeo et al, 2019). Freedom of movement also existed between the UK and the Republic of Ireland for the most part after the latter seceded from the UK in 1922.

Freedom of movement between the UK and its former colonies and the Commonwealth continued until the 1960s, when the Commonwealth Immigrants’ Act 1962 introduced restrictions to entry for those whose passports had not been issued in the UK. In doing so it created ‘an explicitly two-tier, racialised system of citizenship’ whereby all citizens of the UK and Colonies technically had the same legal status, but those who resided outside the UK and whose parentage was also from outside the UK – mostly people of colour – had to acquire a work voucher to enter the UK or be admitted as a student or self-sufficient person (Yeo et al, 2019). These and further immigration restrictions, introduced under the Commonwealth Immigrants Act 1968, were made in the context of growing anti-immigrant sentiment and racism towards ethnic minorities in the UK (Bloom and Tonkiss, 2013; BBC, 2020a). In 1973 a completely new immigration system was introduced when the Immigration Act 1971 came into force, ending any preferential treatment for Commonwealth citizens (Yeo et al, 2019). In the same year, 11 years after the UK started restricting free movement with its former colonies and the Commonwealth, it entered a new free movement area through its membership of the European Economic Community, which eventually became the EU.

The groups of people that are subject to different degrees of immigration control have changed substantially over time in response to labour market needs, public sentiment and the political and economic priorities of the day. Though free movement of people has in some form or other been the historical norm for the UK, the general trend has been towards increasingly restrictive immigration policies that limit migrants’ rights to enter, reside, work and access welfare benefits in the UK. For non-EU nationals, whether entering as migrant workers, asylum seekers or refugees, the opportunities to settle and work in the UK, and access rights and benefits once in-country, have been considerably more strictly limited since the 1970s (Girvan, 2018). The expansion of free movement rights for EU citizens, which developed from the entitlement to work to a more extensive package of social rights regarding education, housing, voting and social security (Bloom and Tonkiss, 2013: 1070–71), was a significant shift in direction. In fact, these rights have not always been distributed equally between EU nationals, as can be seen from the transition measures applied to A8 nationals from 2004 to 2011 and for A2 nationals from 2007 to 2013, making their access to the labour market and welfare benefits conditional1 (Dwyer et al, 2011). In 2020, the Immigration and Social Security Co-ordination (EU Withdrawal) Act 2020 ended free movement for EU nationals seeking to live and work in the UK from 1 January 2021, limited their rights and made them subject to immigration control.

The history of the UK’s immigration system and the progressive introduction of different sets of restrictions have resulted in a highly complex system that distributes rights and entitlements across a wide range of legal statuses. These changes have not only limited the circumstances and conditions under which different groups of migrants are able to reside and work lawfully in the UK, but they have also expanded the circumstances under which they can be categorised as ‘irregular’.

The immigration system as a ‘hierarchy of vulnerability’

Different groups of migrants experience widely divergent rights depending on their immigration status, including access to work and entitlement to welfare benefits, as well as rights related to family reunification and access to education and housing. The different rights and entitlements provided to different groups of migrants based on immigration status creates what has been called a ‘hierarchy of vulnerability’ (Dwyer et al, 2011). As we will explore in more detail in a later section, those groups with the fewest rights will regularly be the most vulnerable to labour exploitation because their options are the most limited. What then, are the different groups of migrants, and which rights are they unable to access?

The groups created by the immigration system, and the different packages of rights they have, are manifold and complex, and it is not possible to outline all of them here. However, at the time of writing, migrants to the UK can broadly be divided into the following categories: workers, students, family members and asylum applicants. Within the worker category are those considered ‘skilled workers’ who tend to have more rights (for example, fewer restrictions on their movement within the UK labour market, longer and renewable visas, and the option of eventually applying for permanent residence), than those who are considered ‘unskilled’, who are usually only granted short-term stays and have no pathway to permanent residence. Table 1 provides a rough overview of the different statuses and attached entitlements to and/or restrictions on people’s right to work and access welfare benefits.

Table 1:

Summary of UK immigration statuses and associated restrictions on right to work and access public funds*

Immigration status Right to work Recourse to public funds
Refugees Yes Yes
Discretionary Leave to Remain Yes Yes
Indefinite Leave to Remain, including Settled Status under the EU Settlement Scheme Yes Yes
Pre-Settled Status under the EU Settlement Scheme Yes Dependent on being able to demonstrate another qualifying right to reside, such as being in work that is deemed ‘genuine and effective’
Family joiners and dependents Yes No
Youth Mobility Scheme Yes No
Skilled Worker visa Yes, but must work for an approved employer, have a certificate of sponsorship and work in an eligible occupation that meets the salary threshold No
Student visa Yes, but limited to 20h per week during term time No
Overseas Domestic Worker visa Yes, but only as a domestic worker in a private household No
Tier 5 Seasonal Worker visa Yes, but only in approved jobs (mainly edible horticulture and ‘ornamentals’) No
Potential Victim of Human Trafficking with a first stage (Reasonable Grounds) NRM decision No No, but entitled to support under the National Referral Mechanism until they receive a Conclusive Ground decision (at present for a minimum of 45 days)
Asylum seeker No, but can apply to work if initial claim takes longer than 12 months No, but entitled to support with housing and £39.63 per week (with £3–5 extra if pregnant or the mother of a child under 3)
Refused asylum seeker No No, but entitled to support with hosing and £39.63 per week if destitute and taking all reasonable steps to leave the UK or unable to leave for an accepted reason.
Irregular migrant No No

* This table has been adapted to the post-Brexit context from Dwyer et al, 2011. It does not include all possible immigration statuses. For a comprehensive list of all immigration statuses and attached rights and entitlements, see:

As can be seen from Table 1, irregular migrants have the most restricted access to work and welfare benefits. Having no authorisation to work, they are not covered by most labour protections, except for some limited protections related to health and safety. Irregular migrants also have no access to social protections, other than limited healthcare through the NHS.

There are a wide range of circumstances and situations that can be classified as ‘irregularity’. The most common conception of irregularity, which is often confused as the only one, relates to people entering a country without the proper authorisation or overstaying their visa and consequently having no leave to remain. There are currently no up-to-date estimates for the size of this population in the UK (ONS, 2019). A Pew Research Centre study (Connor and Passel, 2019) estimated a range for 2017 of 800,000 to 1,200,000, while the Greater London Authority (Jolly et al, 2020) put this estimate at 674,000 (or 809,000 if UK-born children of irregular migrants are included). However, as Walsh (2020) explains, these studies have important limitations and should be treated with caution. Despite the difficulties in counting the number of irregular migrants in the UK with no leave to remain, it is ‘reasonable to assume’ that it is substantial (Walsh, 2020).

Focusing on illegal entry and overstaying as the main routes to irregularity places the emphasis on individual cases committing an offence or breaking the rules, but the reality and the factors leading to irregularity are often more complex. Many of the people who end up classified as irregular in the UK have entered legally and subsequently lost their status, often through no fault of their own (Gardner and Patel, 2021). In cases of domestic abuse, for example, perpetrators purposely withdraw or hide information about their victim’s legal status as a tool to better control them (McIlwaine et al, 2019). People may also end up losing their status because they are unaware of policy changes, cannot afford the fees to renew their visa, receive poor legal advice, cannot afford legal advice, or simply for making a mistake.

Another less often discussed type of irregularity is experienced by people who are residing legally in the UK, but whose right to remain is linked to certain conditions determined by their immigration status. People who breach the conditions attached to their residence can also be classified as irregular and therefore subject to removal. Many of these conditions are employment-related and can determine everything from the type of work the person can do, the sector they can work in, their maximum weekly hours of work, the minimum they must earn and sometimes even the maximum they can earn in order to maintain their status. For instance, someone on a student visa who works more than the permitted number of hours per week during term time is in breach of their conditions for entry. The same is true for someone working on a tourist visa.

This type of irregularity, also termed ‘semi-compliance’, complicates the ‘apparently easy distinction between “regular” and “irregular” migrants’ (Anderson, 2008: 200). It creates a grey area where the decisions about who counts as irregular and who does not become more political than ones based solely on illegal versus legal entry. For instance, what metric is used to decide how many hours a week a student should be allowed to work, or how much someone on a ‘skilled worker’ visa must earn? This latter question in particular has become highly salient in the context of Brexit as, apart from some limited exceptions, the new immigration system only provides visas for ‘skilled’ migrants earning £25,600 or more – a decision which has been extensively criticised by employers in supposedly ‘low-skilled’ or ‘unskilled’ sectors like hospitality (Coghlan, 2020; Rolfe, 2020). ‘Semi-compliance’ also complicates the distinction between regular and irregular migrants as people can, once again, end up in breach of the conditions attached to their immigration status due to no fault of their own. This was true for example for numerous A8 EU country nationals whose employers did not register them under the Worker Registration Scheme, putting them in breach of entry conditions and ‘at risk of being denied all their legal employment rights, as they could be found to be working illegally’ (TUC, 2008: 199).2

Strict immigration-related employment restrictions, such as being tied to a specific employer or sector, make workers highly dependent on their employer and therefore vulnerable to abuse and exploitation. This affects not only those who end up infringing their visa conditions, but also compliant migrants (Shutes, 2012). For example, a person on the Overseas Domestic Worker visa is only allowed to work in the UK for six months and only as a domestic worker. Though they can technically change employer, this is near impossible in practice due to the short visa timeframe. Employers have been shown to take advantage of these restrictions to impose abusive or exploitative conditions, knowing that migrant domestic workers are unlikely to leave or complain when that would mean losing their work and with it their right to remain in the UK (Kalayaan, 2019). It is therefore ‘not only irregular migrants who are unable to challenge violations of labour laws and standards but also those working legally’ (Anderson, 2008: 202).

Finally, the concept of irregularity is further complicated by the fact that people can end up being treated as irregular despite this not being the case. The most notable and well-known example of people wrongly being deemed irregular is, of course, the Windrush scandal. This major policy failure led to people who had arrived in the UK between 1948 and 1973 from the Caribbean and other parts of the Commonwealth, and who had the legal right to live and work in the UK, being denied access to services, wrongfully detained, threatened with deportation and, in at least 83 cases (Javid, 2018), wrongfully deported due to their inability to prove their right to reside in the UK.

A less well-known example of people being wrongly treated as irregular are cases where authorities end up detaining victims of human trafficking who have the right to remain in the UK under the Modern Slavery Act 2015 (LEAG, 2019). In the UK, the National Referral Mechanism (NRM) is the framework for the identification of potential victims of modern slavery. To be recognised as such and access support, potential victims must be referred to the NRM by a ‘first responder’, an organisation authorised to carry out an initial risk assessment and to refer cases into the NRM, for further assessment by a competent authority. First responders currently include local authorities, the UK Visas and Immigration, and several NGOs, among others (Home Office and UK Visas and Immigration, 2022). Both the police and the Gangmasters and Labour Abuse Authority (GLAA), the agency responsible for the prevention, detection and investigation of worker exploitation and related modern slavery offences across all labour sectors in England and Wales, as well as for licensing and monitoring the gangmasters licensing scheme across the UK, are also first responders. However, as evidence shows, victims with insecure immigration status are often reluctant to come forward and report the abuse to the police and the GLAA, given the lack of secure reporting mechanisms, understood as the assurance that the individual’s personal data will not be passed to the authorities and used to carry out immigration enforcement actions against them (FLEX and LEAG, 2020).

As the complex picture we have presented so far shows, irregularity is not a clear-cut status, but a multi-faceted collection of statuses that encompasses various shades and shapes. When considering how irregularity is created, there is a tendency to focus on the actions of individuals – whether it is crossing borders without authorisation or violating visa conditions – but this is only part of the story. States, through immigration policy, have a considerable role in creating and shaping irregularity. By delineating which immigration routes are opened and for whom, the state creates spaces for both regular and irregular migration. When regular routes of migration are closed, pockets of irregularity are likely to open up, especially if push and pull factors for migration remain unchanged. Similarly, by determining the conditions that migrants must meet once in-country to maintain their residence rights, states also shape who is at a higher risk of becoming irregular. The more restrictive and complex these conditions are, the higher the risk of non-compliance and irregularity. As we will explore later in the article, the end of free movement with the EU and the subsequent redesign of the immigration system has led to a more restrictive system and, with it, to a higher risk or irregularity. The vulnerabilities created by the lack of immigration status are particularly heightened in the UK, due to its ‘hostile environment’ policies.

The UK context: ‘hostile environment’ policies and risk of exploitation

Research exploring labour exploitation of adult migrants conducted by the EU Agency for Fundamental Rights (FRA), building on eight country-specific reports, including one on the UK (FRA, 2017a), found that ‘vulnerability linked to residence status is the most important risk factor causing or contributing to labour exploitation’ (FRA, 2019: 67). Migrants with an irregular immigration status tend to have fewer alternative avenues of employment, which increases their dependence on exploitative employers and strengthens the position of the employer who can easily use the threat of arrest and deportation to keep workers in situations of exploitation (FRA, 2019). The FRA’s prior research found that ‘victims of severe labour exploitation who are in an irregular situation of residence are discouraged by their status from reporting to any public authority’, resulting in exploitation going undetected by the police and labour inspectorates (FRA, 2017b: 41).

Vulnerability to exploitation is not, however, intrinsic to irregular migrants. Instead, it occurs when a lack of status is tied, through policy choices, to more limited rights and access to support. It varies from country to country, as different policy approaches result in varying levels of vulnerability.

The UK’s policy environment is particularly restrictive as a result of the ‘hostile environment’ (recently rebranded by the government as the ‘compliant environment’) – a set of policies aimed at identifying and reducing the number of immigrants in the UK with no right to remain (Taylor, 2018). Introduced mainly through the Immigration Acts of 2014 and 2016, these measures restrict irregular migrants’ ability to work, study, rent property, drive, have bank accounts, and access social protections like healthcare and benefits. Service providers and public authorities, from employers to landlords and banks to the police, are required to carry out immigration document checks and share data with the Home Office for immigration enforcement purposes. Failure to do so can result in fines or criminal prosecution. Immigration status data is also shared between government departments, such as labour inspectorates, and the Home Office.

A key hostile environment policy is the Offence of Illegal Working, introduced under the Immigration Act 2016. The Offence fuels exploitation by pushing migrants into precarious jobs in the least regulated sectors of the economy and making them fearful of seeking help. It also strengthens one of the main tools exploitative employers use to coerce and control migrants in exploitative situations: the threat of reporting them to the authorities (FLEX and LEAG, 2020). Being and working in the UK without authorisation was already prohibited under UK law, carrying the risk of deportation, but the Immigration Act 2016 made ‘illegal working’ a criminal offence in its own right, punishable by an unlimited fine, a six-month custodial sentence and the confiscation of any income earned during the relevant working period. As a result of the Offence, victims of exploitation are even more likely to go unidentified and unsupported because they cannot come forward without fear of punishment,3 and abusive employers are rarely pursued to justice. For comparison, in most EU Member States, irregular residence – while it remains a key source of vulnerability for workers – does not nullify a person’s right to be paid for their work and, in countries like Luxembourg, employers have a duty to pay migrant workers with an irregular status their salaries as well as social contributions (FRA, 2011: 48).

Another main feature of the UK’s hostile environment policies is that they engage statutory agencies, such as the police and labour inspectorates, in enforcing immigration policy by reporting cases of potential ‘illegal working’ and by carrying out simultaneous operations aimed at identifying irregular migrants. National and international research shows that working with immigration enforcement makes labour market and law enforcement agencies less effective in delivering their primary functions by creating mistrust, especially with migrant communities (FRA, 2011; FLEX and LEAG 2020). Prioritising immigration enforcement over the enforcement of labour rights means that people in situations of exploitation are unable to seek help and hampers the government’s efforts to end modern slavery. In sum, any increase in irregular populations in the UK is likely to lead to an increase in labour abuses and exploitation, including those severe forms that fall under the Modern Slavery Act 2015.

Brexit and the expansion of irregularity

The UK government’s decision not to open a general route of entry for low-paid work following the end of free movement with the EU, is likely to be the most significant factor leading to an increase in irregularity. The Skilled Workers visa under the new points-based system (PBS) excludes the vast majority4 of people earning less than £25,600 a year, and anyone earning less than £20,480, from accessing work visas (Home Office and UK Visas and Immigration, 2020a). The only remaining immigration routes available for anyone earning under the new PBS salary threshold will be the Overseas Domestic Worker visa, the Tier 5 Seasonal Worker visa for agricultural workers and other temporary permits under Tier 5.5 These routes will not respond to the continued demand for migrant workers in low-wage sectors like cleaning, construction, hospitality and warehousing.

The lack of safe and regular migration routes for low-paid work post-Brexit is a significant concern, as people are still likely to migrate for this type of work but will have to do so through irregular and often more dangerous channels. Studies show that while immigration policies have become more restrictive, immigration flows have continued to increase (Castles, 2010; Hollifield et al, 2014; Clemens et al, 2018). Whereas it is difficult to assess whether these policies are ineffective or whether other factors (for example, inequality between countries of origin and countries of destination) are leading to these increases,6 they are likely to result in unintended policy outcomes, such as higher rates of irregular migration and increased dependence on and vulnerability to exploitation among migrants by brokers, smugglers and employers, both en route and in-country (Gathman, 2004; Van Liempt and Doomemik, 2006; Parizot, 2008; Napier-Moore, 2017; Duvell et al, 2018). For instance, a multi-country study of migration from Africa to Europe found that immigration restrictions in the EU ‘do not, and probably cannot, stop migration’ and instead simply make it more challenging, forcing people to take greater risks, look for new routes and pay smugglers more (European Commission, 2016). A House of Commons Foreign Affairs Committee (2019: 3) report on the UK response to the 2015 refugee crisis supports these findings, noting that a ‘policy that focuses exclusively on closing borders will drive migrants to take more dangerous routes, and push them into the hands of criminal groups’.

Immigration restrictions tend to be especially ineffective in reducing migration in contexts where there is a high demand for migrant labour (Triandafyllidou and Bartolini, 2020). This is most often the case for jobs the domestic labour force is unable to fill due to skills gaps, or unwilling to fill due to low pay, lack of prestige and poor working conditions. For instance, in southern Europe, the demand for what is referred to as ‘cheap labour’ has led to an increase in migration from Senegal and Ghana despite more restrictive immigration policies (MAFE, 2013). We can expect to see a similar dynamic in the UK, where several low-paid sectors are highly reliant on, but since Brexit unable to recruit, workers from the EU. For example, in 2019, EU citizens made up 19.7% of all workers in elementary occupations, 13% of process, plant and machine operatives, 7.7% of caring, leisure and other service occupations and 5.4% of sales and customer service occupations (ONS, 2020). Research shows that a significant proportion of EU workers employed in the UK would be ineligible to enter under the new PBS, including 90% of workers in transport and storage, 85% in hotels and restaurants, and 59% in construction (IPPR, 2020). Even in agriculture, where the Tier 5 Seasonal Worker visa provides an option for regular migration, we are likely to see an increase in irregular workers. This is because the sector previously relied on 90,000 seasonal migrant workers per year, but has so far only been able to recruit a small proportion of that under the Tier 5 visa scheme (Doward, 2020; Swire, 2020).

The government’s response to industries saying they will face significant labour shortages if unable to recruit migrant workers has been to say that they will need to move away from ‘a reliance on cheap labour from Europe and instead concentrate on investment in technology and automation’ (Home Office and UK Visas and Immigration, 2020a). This will be challenging in service sectors like cleaning, hospitality and retail, which require manual dexterity and interpersonal skills not easily replaced by artificial intelligence or automation.

Though COVID-19 lockdowns led to reduced employment in some of the sectors mentioned earlier, especially hospitality and construction, we have since seen labour shortages across the UK economy (ONS, 2021). In February 2022 there were nearly as many vacancies as there were people unemployed, indicating a very tight labour market with health and social care, hospitality and retail in the top industries struggling to recruit workers (IES, 2022). These shortages are likely to continue, at least in the short term, particularly for jobs that do not meet the skills and salary requirements of the new PBS. The risk is that some employers, unable to recruit from abroad and unable to attract workers from the domestic labour force, will turn to irregular workers. We are seeing some examples of this already, for instance with the GLAA finding cases of people on student visas being exploited in the care sector and noting that, due to labour shortages, there is a real risk that ‘opportunists and unscrupulous employers may look to fill this void by exploiting vulnerable workers’ (GLAA, 2021). Labour shortages may act as a pull factor, encouraging people working in sectors without regular routes to use alternatives, such as overstaying and different types of semi-compliance, including people working on visitors’ visas or outside of the sector permitted by their visa.

The second major change that will contribute to an increase in irregular migrants is that all EU citizens7 (except Irish nationals) and their family members living in the UK must have registered through the EU Settlement Scheme (EUSS) in order to retain their residence rights. The deadline for applying was 30 June 2021 for those who were resident in the UK by 31 December 2020, when the transition period ended. Successful applicants have been granted either settled status (indefinite leave to remain, based on five plus years of evidenced residence) or pre-settled status (limited leave to remain, to be converted to settled status once five years of residence can be evidenced). EU nationals and/or their family members who have not successfully registered through the EUSS yet remain in the UK after 30 June 2021 are at risk of becoming irregular.

Most eligible applicants should have had no problems applying for and getting pre-settled or settled status. However, there are people who did not apply or were unable to, whether because they are vulnerable, struggle to navigate the application system or could not provide proof of citizenship, residence or, in the case of non-EU nationals, their relationship to an EU citizen (Sumption and Fernández-Reino, 2020). Additionally, there will be EU citizens who have applied to the EUSS but (i) were refused status and yet remain within the UK or (ii) do not, for whatever reason, convert from pre-settled to settled status once they are entitled to, but remain within the UK. At the end of December 2021, 205,400 (3%) of EUSS applications had been refused and 2,507,400 (41%) of concluded applications were for pre-settled, not settled status (Home Office, 2022). Vulnerable groups, such as those who have experienced exploitation or homelessness, are especially likely to struggle to convert from pre-settled to settled status in the future (Sumption and Fernández-Reino, 2020). Furthermore, there are a number of restrictions that must be complied with to maintain pre-settled status, such as not being away from the UK for more than six months in any given 12-month period (Hickman, 2020).

It is difficult to estimate how many people will end up without an immigration status due to not securing their status under the EUSS, as there is no concrete data on the number of existing EU citizens and their family members in the UK, nor how many belong to vulnerable groups. In fact, it was initially estimated that there were approximately 3.7 million EU citizens living in the UK (Vargas-Silva and Walsh, 2020) and that as many as 185,000 people could end up irregular if even 5% of eligible applicants fail to secure their status. The actual number of applicants by 31 December 2021 was much bigger, with a total of 6,385,500 applications received (Home Office, 2022).8 A comparison of various registration schemes carried out in the UK, Greece, India, Spain and the US suggests that it will be very difficult for the EUSS to achieve 100% coverage through just one round of registrations, even with significant resources put into publicity and outreach campaigns (Clay et al, 2019). In almost all cases where high levels of coverage have been achieved, a second phase of registrations was needed (Clay et al, 2019). The government announced the possibility of submitting late applications and published guidance on what would be considered ‘reasonable grounds’ for failing to meet the deadline, including cases of modern slavery (UK Visas and Immigration, 2021).

The EUSS did not have to lead to an overnight loss of immigration status for anyone. The fact that it is likely to have done so is the result of a political choice. There are a number of decisions the UK government could have made to reduce the likelihood of people becoming irregular as a result of not registering. It has already made some of these choices, for example removing the £65 registration fee that applicants initially had to pay to register and which civil society organisations campaigned against in the knowledge that it would act as a barrier for registration (Helm, 2018). The government could also have removed the cliff-edge application deadline by replacing the constitutive system – where people had to make an application to secure their status – with a declaratory system that would have granted settled status to everyone who was eligible (Jablonowski, 2020). People would still have needed to register to receive proof of their status, but a declaratory system would have removed the risk of falling into irregularity.

There are further issues with the EUSS that could lead to people becoming irregular or being treated as though they are irregular, despite having residence rights. The first is that the immigration status granted by the EUSS is ‘digital only’, meaning people have no physical document to evidence their immigration status.9 Once again, most EU nationals and their family members should have no problems using a digital-only status, but those who are vulnerable or face digital illiteracy issues, may struggle to prove their status (Bulman, 2020; Tomlinson and Welsh, 2020). Furthermore, EU citizens now depend on employers, landlords, universities and other private individuals and public bodies with a responsibility to check immigration status to understand the new system and how to access their information.

Though aimed at irregular migrants, the UK’s hostile environment policies have a spill over effect on all migrants who are expected to demonstrate their entitlement to rights and support, making a range of immigration statuses insecure ((FLEX/LEAG, 2017). UK nationals, as well as EU citizens and non-EU nationals with valid leave to remain, have been caught up in the hostile environment system and denied access to rights and services as a result of errors in the application process, problems with data retained by the Home Office and discrimination (House of Commons Home Affairs Committee, 2018). Those workers employed under more restrictive visas, such as the Tier 5 Seasonal Worker visa are also put at heightened risk of exploitation. Though workers on the Tier 5 visa have a lawful status, the restrictions attached to their visa, such as only being allowed to stay for six months, being limited to working on farms and having to apply for permission to change employer, give their employers undue leverage, which greatly heightens the power imbalance at work. Unscrupulous employers are able to abuse the fact that Tier 5 migrants will often find practical barriers trying to change employers and therefore face the stark choice of returning to their country of origin without having earned back on the investment they have made to secure a job in the UK, remaining in the UK without status, or continuing to work in exploitative conditions. These practices lead to unfair competition, which pushes to lower the standards of the sector as a whole. A FLEX and Fife Migrants Forum assessment of the UK’s Seasonal Workers Pilot found a serious risk of human trafficking for forced labour on the scheme, given the number of ILO indicators met for each of the three dimensions of forced labour (FLEX and FMF, 2021). Risk of labour exploitation associated with temporary work visas is extensively evidenced by examples from around the world (FLEX, 2019; FLEX and FMF, 2021).

Another risk factor comes from the ability of the government to change the immigration rules through secondary legislation by introducing new Statutory Instruments. Statutory Instruments allow Ministers to change the rules quickly and with less parliamentary or public scrutiny than primary legislation receives. We have already seen this happen with expansion of the Tier 5 Seasonal Worker visa from a 2,500-worker pilot to a 30,000-worker scheme without consultation with worker representative organisations or evaluation.10 Similarly, the government has laid immigration rules before parliament that will make rough sleeping grounds for refusal or cancellation of permission to be in the UK (Home Office and UK Visas and Immigration, 2020b).

Finally, a contextual factor driving vulnerability to exploitation in the UK among all workers is the state’s insufficient investment in enforcing labour standards and the fragmented nature of its enforcement system (FLEX, 2017). In addition, a number of rights must be enforced by individuals through the employment tribunal system – a mechanisms which has been shown not to work for those groups most vulnerable to exploitation (Citizens Advice, 2019; Cominetti and Judge, 2019). The UK’s labour market enforcement system is one of the weakest in Europe, with an inspector to worker ratio well below the ILO’s recommended one to 10,000 (FLEX, 2017).

Overall, it is feasible to anticipate that the likely rise of irregular migration due to Brexit, coupled with an increasingly hostile approach in UK immigration policy and the lack of effective enforcement of labour standards, will result in a highly vulnerable workforce. The picture is even more bleak when considering the impact of the economic downturn resulting from the COVID-19 pandemic, which is increasing unemployment and poverty across the world, pushing people to migrate in search of better opportunities.

To meet prevention obligations, a range of measures is needed

The UK has an obligation and aim to prevent modern slavery under several instruments and strategies. These include the UK’s national Modern Slavery Act 2015 and Modern Slavery Strategy (UK Government, 2014); the Council of Europe Convention on Action against Trafficking in Human Beings; the United Nations Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children; and Sustainable Development Goal 8.7 which commits governments to ‘take immediate and effective measures to eradicate forced labour, end modern slavery and human trafficking […] by 2025’ (UN, 2015). Yet, as we have demonstrated, the UK government’s immigration policy decisions often undermine these goals and agreements.

The risks of heightened exploitation posed by Brexit present a challenge to the UK that can be met using a range of measures. A measure that could directly alleviate this risk would be to open safe and regular immigration routes into low paid jobs with minimal restrictions on people’s rights, in particular their right to work, access social security, and extend their visa. Adding occupations to the points-based system’s Shortage Occupation List, as has been done recently with care work (Department of Health and Social Care et al, 2021), provides one such alternative. However, as always with high-risk sectors, robust monitoring and enforcement of labour standards is needed to mitigate the additional risks resulting from immigration, such as the risk of illegal recruitment fees, or employers passing the costs of migration (visa fee, health surcharge and so on) onto workers. That is, introducing a viable alternative that recognises and responds to the continued demand for labour migration into these jobs. Such a response would demonstrate a commitment to the prevention of Modern Slavery over other political aims.11

A general route into low paid jobs that could be monitored in relation to market demands would help mitigate the factors that pull workers into irregularity and help reduce the risk of labour exploitation. Alternatively, as one of its key recommendations to prevent irregularity, the FRA has suggested that EU countries, which at that time included the UK, fill labour market shortages through targeted labour migration programmes, ‘especially for those sectors particularly at risk of labour exploitation’ (FRA, 2019: 19). Though the risks of exploitation associated with such programmes have been highlighted by previous research (FLEX, 2019), we recognise that having regular routes, even restricted ones, is less risky than no route at all. Any temporary programmes must, however, embed protections to mitigate potential harms that may arise by the interaction of immigration with other policies and be accompanied by targeted, proactive state enforcement of workers’ rights.

The government should also make the EUSS a declaratory rather than a constitutive system, so that people who have failed to register do not automatically lose their residence rights and become irregular. Though it may seem irrelevant now that the EUSS application deadline has passed, it remains important considering the vulnerable groups who may never have applied and the approximately 2.5 million people who (as of 31 December 2021) had pre-settled status (Home Office, 2022) and could lose their residence rights if they fail to convert to settled status in the future. Additionally, there are smaller changes that could be made, such as providing EU nationals with physical proof of their status and ensuring that people are supported to change their pre-settled to settled status once they have been resident for the requisite time.

In addition, all policymaking and statutory agency activity needs to take a ‘continuum’ approach to labour exploitation (FLEX and LEAG, 2016). This means recognising that labour exploitation is part of a spectrum that ranges from decent work through to progressively serious labour law violations, culminating in severe exploitation, including offences that fall under the Modern Slavery Act 2015. Labour abuses that may seem less impactful in isolation can accumulate over time to a more general undermining of the conditions of decent work, enabling more extreme forms of violations, including forced labour, to flourish (Skrivankova, 2010). Therefore, in order to effectively eradicate labour exploitation, the continuum approach holds that states must not only tackle the most severe cases but also ensure that fundamental labour rights are respected and upheld.

The UK government is currently pursuing a major reform of labour market enforcement, which will create a new Single Enforcement Body for employment rights (Department for Business, Energy & Industrial Strategy and the Home Office, 2019). This presents a key opportunity to embed a continuum approach going forward, such that inspectors have a menu of proportionate and flexible powers from which to select and tackle the circumstances and abuses they identify in workplaces. An understanding of the links between labour abuses and severe forms of exploitation could inform the development of prevention strategies, which should take into account the contextual and structural factors shaping the experiences of workers in high-risk sectors. In order to ensure the efficiency of this new approach to enforcement, international best practice can provide guidance for more appropriate and evidence-based funding of labour market enforcement, staffing and tactics. At a minimum, this should include adopting the ILO recommended one inspector per 10,000 workers (Weil, 2008) and ensuring 60% of labour inspections are proactive and prioritised for highest-risk workplaces, while only 40% are reactive, responding to accidents and complaints (World Bank, 2011).

Finally, to reduce the vulnerability that irregular migrants face, the government should repeal the Illegal Working Offence and end other hostile environment policies that have been shown to create vulnerability and prevent those at highest risk of exploitation from seeking support. It should also direct labour inspectorates not to conduct simultaneous or coordinated inspections with immigration enforcement, as this negatively affects their labour market enforcement responsibilities, and introduce secure reporting so that irregular migrants can go to the police and other authorities without fear of immigration repercussions.

While the immigration and LME systems, and their intersection, are key elements of a more robust policy platform from which to tackle modern slavery, other structures and practices must also be considered. The COVID-19 pandemic exposed a raft of pre-existing inequalities that create a labour market permeable to worker harm, including modern slavery (FLEX, 2020). From the understanding that vulnerability is not intrinsic but constructed, we can see how these wider policy areas become relevant if we wish to build resilience to exploitation into our economy and society.



A8 nationals are nationals of the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia, which joined the EU in 2004. A2 nationals are nationals of Bulgaria and Romania, which joined the EU in 2007. The UK was one of only three countries to allow A8 nationals immediate access to their labour market, albeit with restrictions.


The Worker Registration Scheme was a transitional measure introduced by the UK government to limit A8 EU country nationals’ access to the labour market. Under these measures, workers had to register within 30 days of getting or changing a job in order to gain the ‘right to reside’ after a year. The A8 countries are Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia.


A fear that is not unfounded, as evidence shows that even recognised victims of trafficking have been held in UK detention centres (LEAG, 2019).


Exceptions to the salary threshold can be made for some based on their ‘specific job offer and qualifications’ and for a small number of jobs on the shortage occupation list (Home Office and UK Visas and Immigration, 2020a).


Research that does find immigration restrictions to be effective in reducing migration (see for example Helbling and Leblang, 2018) often only look at the impact on migration through ‘legal’ routes, as there is little to no quantitative data available on irregular migration flows.


We will use ‘EU citizens’ to refer to EU, EEA (Iceland, Liechtenstein and Norway) and Swiss citizens throughout.


This figure includes a small proportion of repeat applications and invalid applications.


At the time of writing this aspect of the EUSS was still being debated in Parliament.


A review of the 2019 version of the Seasonal Workers Pilot was published by the UK government 24 December 2021, along with the announcement of the expansion of the scheme to 30,000 workers. For an analysis of this review, please read ‘FLEX response to the government’s review of the first year of the Seasonal Workers Pilot’ (FLEX, 2022).


Since Brexit there has been extensive debate where migration, especially ‘low-skilled’ migration, has been framed as a direct cause of low wages and poor working conditions that is, if migrants’ access to the UK labour market is restricted, employers will have to raise wages and improve conditions to attract more UK workers (see, for example, Redwood, 2021). While this may seem like a compelling argument, it fails to consider the impact of labour standards and especially their enforcement in allowing employers to use migrant workers to ‘undercut’ terms and conditions.


This work was supported by Unbound Philanthropy and Paul Hamlyn Foundation.


Lucila Granada, CEO, and Meri Åhlberg, Research Manager, both work for Focus on Labour Exploitation (FLEX), a research and policy organisation working to end labour exploitation. This article builds on FLEX’s analysis of risks of exploitation linked to immigration restrictions, which is the result of the collective effort of numerous individuals who have contributed to FLEX’s work over the years. The authors would also like to thank Colin Yeo at Free Movement for his analysis of the history of the UK’s immigration law.

Conflict of interest

The authors declare that there is no conflict of interest.


Meri ÅhlbergFocus on Labour Exploitation (FLEX), United Kingdom

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Lucila GranadaFocus on Labour Exploitation (FLEX), United Kingdom

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