British politics have been dominated by the desire to avoid any kind of customs barrier between Northern Ireland and the Republic, lest peace in that province of the United Kingdom be threatened by a renewal of conflict. Yet this honourable aim, to which all other objectives of British policy have been subservient, has been pursued in almost wilful ignorance of the wishes of the people of Northern Ireland, save one sectarian segment of it, the Democratic Unionist Party. They do not even have the support of a majority of Ulster Protestants, as a recent Irish Times poll demonstrated.

The DUP’s case has always been that Northern Ireland is, and should remain, “as British as Finchley” – the north London constituency that was represented in the House of Commons by Margaret Thatcher. It is for this reason the DUP has resisted one easy answer to the Irish border question. The EU had proposed that after Britain leaves the European Union, if and when it does, there would be an international border between Britain and the EU in the Irish Sea.
That would mean customs and immigration checks would be performed either physically on board the ferries that ply the Irish Sea, or at the ports of arrival on the British side. And Northern Ireland would remain inside the EU customs union with the Irish Republic, solving the so-called backstop problem.