Editorial: Our long article today looks at an enduring Irish Sea border, not one that has gone away

(This editorial is about our long-read article on the Irish Sea border – click here to read that article by Owen Polley)​

By early next summer it will be 10 long years since the Brexit referendum narrowly endorsed a UK departure from the EU.​

For much of the period afterwards, Northern Ireland became the principal dispute between Britain and Europe.

After a long standoff between the two sides, the matter was decisively resolved – in favour of the Republic of Ireland and the EU.

The exact process as to how that happened is a long, complicated and contested one. Suffice to say, Theresa May was a weak negotiator, as supporters of Boris Johnson later claimed. And Mr Johnson himself was dishonest – talking tough about no internal UK barrier, then agreeing an almost complete one, then denying he had done so.

Unionists hardly covered themselves in glory during this time, often sending mixed signals as to what would and would not be acceptable. It is not unreasonable to surmise that both London and Brussels detected a lack of real, serious unionist opposition to a sea border, of the sort that nationalists were clearly going to display if the land border was hardened to even the slightest degree.

Talk by some unionists of the potential ‘best of both worlds’ merely heightened the sense that unionists were weak or venal or both, ultimately more interested in money than the principle of NI being an unfettered part of the UK.

While, in fairness, it is important to acknowledge that trade details were so complicated that it is not surprising that unionists and indeed most observers failed to grasp what was happening, and while it is also fair to say that unionist options were limited, a serious mistake was made when the DUP returned to Stormont last year. It implied that the sea border was gone.

As Owen Polley explains in a long article on pages 14, 15 and 19 the barrier is there, it has wide scope and has only got harder.