Europe invites scepticism but quitting is no easy option

Within hours of David Cameron striking a deal with other EU leaders late on Friday night, it emerged that the Secretary of State for Northern Ireland Theresa Villiers was one of the six Cabinet ministers who would campaign for a Brexit.

This is a blow for the prime minister, as Ms Villiers was seen as a close ally. Michael Gove, who is also joining the Leave campaign, was another Cameron ally in the Cabinet.

That Boris Johnson is backing Brexit will be little surprise, as he is not a loyal friend to the prime minister, but it is still a coup for ‘Out’ and a deep disappointment for Mr Cameron.

On Saturday Arlene Foster quickly established the official DUP position in support of the UK quitting the EU. With Jim Allister of the TUV and David McNarry of Ukip firm supporters of Brexit, this puts pressure on Mike Nesbitt’s Ulster Unionists. No party with the word unionist in its name will want to be seen as reticent in defence of British sovereignty.

But Mr Nesbitt has good reason to pause before, first, deciding on the position of the party and, second, deciding on how binding that position will be on senior members.

While unionism and euroscepticism tend to go hand in hand (scepticism this newspaper strongly shares) there is little polling evidence to suggest that a clear majority of unionists is so sceptical as to support the nuclear option of Brexit.

The points made by Mrs Foster (that the renegotiation secured little) and Ms Villiers (about sovereignty) are valid. The question is how much control can we actually get back alongside free trade deals, and what will the cost of that gain be?

There is also a matter that few unionist quitters addressed over the weekend: any threat to the UK itself from a Brexit by, for example, a new Scottish referendum.

Leaving might yet be the least bad choice. But we should not pretend it is an easy one.