The DUPs numerically significant 10 MPs, above with party leader Arlene Foster, could rescue their legacy by joining the majority in the House of Commons in favour of the sort of softer Brexit that sees the UK staying within the customs union, but outside the EU

An exit from the customs union necessitates some form of customs boundary, somewhere.

A harder border with the Irish Republic seems to appeal to more fevered elements within unionism, so it is worth considering why this would in fact weaken the Union.

The Union only exists for as long as most people in Northern Ireland want it and in recent years it has looked increasingly secure as poll after poll indicated that a growing chunk of “nationalist” voters would not vote to change the status of Northern Ireland.

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Letters to Editor

This trend was a quiet success for Unionism over the past 20 years.

Now do these soft nationalists secretly keep a portrait of the Queen in their living rooms? I doubt very much that any of them are closet monarchists, though I’m sure many will watch the royal wedding today.

They are people who at heart feel Irish but, with an invisible border and decades of equal treatment in Northern Ireland, they have been content and don’t want the upheaval a change of jurisdiction would cause.

Hardening the invisible border we currently have risks upsetting the delicate balance in these people’s minds and that weakens the Union.

The alternative route for the UK to leave the customs union, is to leave Northern Ireland inside and create an internal border in the Irish Sea.

If the result of unionist and DUP support for Brexit is an internal border separating us from the rest of the UK, then it will have to be viewed as a massive own goal by unionism’s leadership.

There is, however an alternative route for the DUP’s numerically significant 10 MPs, by which they could rescue their legacy.

Join the natural majority which exists within the House of Commons in favour of the sort of softer Brexit that sees the UK staying within the customs union, but outside the EU.

Some 52% of the people voted for some sort of Brexit, and their wishes must be respected, but it is nonsense to argue that 52% voted for the hardest possible Brexit and for the 10 DUP MPs it would be folly to smash the Union into an unnecessarily hard Brexit.