The Common Travel Area (CTA) is an arrangement whereby UK legislation provides there are no border (i.e. passport) controls across the land border on the island of Ireland. Common EU membership has also ended customs controls. Any restriction on freedom of movement over the land border engages compatibility with the Belfast/Good Friday Agreement (GFA 1998). The planned Brexit, including Northern Irish withdrawal from the customs union and single market, changes this context, particularly as the leave campaign in the June 2016 EU referendum had a determined focus on the UK ‘taking back control of its borders’. At the same time assurances have been given that the UK does not wish for a return to the ‘borders of the past’ and the expressed aim is for the border to be as ‘seamless’ and ‘frictionless’ as possible. The practical arrangements for this are yet to be determined and much confusion remains on whether the expressed desire for an ‘invisible’ border is practically possible (given the nature of the proposed Brexit).