Ireland was the only colony that Britain seriously attempted to integrate into the metropolitan UK, but like Algeria was for France, this proved to be a huge failure.

The artificially-defined six county rump statelet was merely putting off the inevitable. The British people (English, Scots, and Welsh) see N.I. as a foreign land and have supported Irish unity against the policies of the British political class.

The religious hatred which was fostered by the local N.I. political élite with historical backing by London proved to be a huge contradiction for British policy. Religious apartheid helped tie the protestant majority to the 'benefits' of the union (socio-economic dominance over local catholics) thus preserving the territoriality of the British state, whilst making NI's social and civic integration into the UK impossible.

Westminster has realised the failure of this integration. Power-sharing in NI is seen as an inevitable route to Irish unity, and political unionism can only tactically delay but cannot reverse this course.

Most importantly of all, with the abandonment of institutionalised discrimination against Roman Catholics any supposed benefits of retaining the British union become more difficult to argue for.