This chapter examines how reforms to the planning system in England since 2010 have affected the capacity of the system to deal effectively with environmental problems. The period 2010 to 2016 witnessed a progressive diminution of the environmental role of planning, legitimised by ideological desires to deregulate development and exacerbated by public sector austerity. Until the Brexit vote of 2016, however, there remained the stabilising framework of European Union environmental policy, which offered a system of bedrock protections. Since then, the planning–environment interface has been buffeted not only by planning reforms but also by the repercussions of Brexit for environmental policy. On the one side have been ministers exploring the new freedoms Brexit has given them to pursue opportunities for regulatory flexibility and streamlining. Set against these pressures, the implications of climate change, the nature crisis and the emergence of a new domestic environmental governance regime all push in the direction of firmer, long-term, goal-driven frameworks for planning. Should the latter prevail, the need to address ‘state failure’ on the environment could help to reverse decades of ‘planning failure’, but this outcome is far from guaranteed.