THIS week’s European Council was supposed to be “the moment of truth” on Brexit.

The time when the EU28 comrades came together to agree the terms of the UK’s withdrawal from the Brussels bloc and pointed to another summit in mid-November to agree the political statement on post-Brexit Britain’s future relationship with the EU.

But the sweetness and light will not materialise so soon as disagreement over something which both sides believe will hopefully never come to pass has knocked things off course: the backstop.

Or, rather, the backstop to the backstop.

Back in December, the UK and EU agreed in principle that, should a trade deal not be agreed in time – by the latest date of December 2021 – then a backstop plan should apply to keep the Irish border open, enabling frictionless trade.

The EU wanted a carve-out for Northern Ireland to stay in the customs union but this was vehemently opposed by Theresa May. When the DUP got whiff of the suggestion all hell broke loose. Ruth Davidson, the Scottish Conservative leader, hurried down to London to tell the Prime Minister, in no uncertain terms, that any carve-out for Northern Ireland would undermine the integrity of the Union.

It would lead to a similar demand by Nicola Sturgeon for Scotland and a constitutional hare would have been let out of the traps. Indeed, the First Minister in a speech in London on Monday said, in such circumstances, the SNP Government would demand a “differentiated approach”.

Mrs May’s suggestion was an all-UK backstop. Fine. But Michel Barnier, the EU’s Brexit supremo, continued to demand that a Northern Ireland carve-out should remain available in case the UK-wide arrangement lapsed before the trade deal was finalised.

So will the elusive “moment of truth” ever arrive? Of course, it will because the alternative, a no-deal, is unthinkable for both sides.

Chances are, brinkmanship will mean that, as the Taoiseach Leo Varadkar alluded to yesterday, the key summit will come not in November but December.

The wording on the backstop will ultimately be fudged so that each side can claim victory and, after a night of table-banging, finger-pointing eleventh-hour diplomacy, Mrs May and Messrs Juncker, Tusk and Barnier will emerge blinking and smiling into the chill Brussels dawn to declare an historic deal has been done.

By then Brexit really will mean breakfast and probably a full English.