Negotiating its withdrawal from the European Union was a painful, protracted process for the United Kingdom. It was also a process that saw it concede ground to the EU on most withdrawal issues. Unsurprisingly, the EU was often presented in much of the UK media and particularly by supporters of Brexit as inflexible and short-sighted. There were accusations that it was not only refusing to show any appreciation of the UK position, but also intent on “punishing” the UK into leaving. Such accusations overlook the fact that, on the question of Northern Ireland, at least, the EU adopted a position of relative flexibility. Conscious of the challenges that Brexit posed for the island of Ireland, the EU and the UK agreed a dedicated Protocol providing for a set of arrangements unique in the EU's external relations. While the EU is quick to point to the flexibility it has shown in agreeing special terms for Northern Ireland, these are not without their problems for the UK and the EU.

That the Withdrawal Agreement contains a dedicated Protocol on Ireland/Northern Ireland is due to a range of challenges that UK withdrawal from the EU poses for Northern Ireland and the island of Ireland more generally and, importantly, the EU's and the UK's willingness to respond to these challenges. The willingness was evident as soon as then Prime Minister Theresa May, on 29 March 2017, submitted her letter to Donald Tusk, president of the European Council, notifying the EU of the UK's intention to withdraw, and in so doing setting in motion the Article 50 withdrawal process. That notification recognized the need to pay attention to the UK's “unique relationship” with Ireland and “the importance of the peace process in Northern Ireland”. Hence, a “return to a hard border” on the island of Ireland should be avoided and the Common Travel Area (CTA) between the UK and Ireland maintained. Moreover, the UK had “an important responsibility to make sure nothing is done to jeopardize the peace process in Northern Ireland, and to continue to uphold the [1998] Belfast [‘Good Friday’] Agreement”.