A backstop with time-limit might end up being permanent too

The panel was made up of the Tory MP Graham Brady, Kate Hoey MP, Ray Bassett, a former Irish diplomat, and Arlene Foster.

The DUP leader Mrs Foster made an important observation. “We cannot have internal customs borders within the United Kingdom,” she said. “Actually when you think of the amount of trade we do East-West and West-East it completely blows out of the water the North-South trade. I’m not saying the North-South trade is not important – it is of course important – but our East-West trade is much more important.”

This point is little made: that with the exception of agriculture and related food, where there is serious cross-border trade, the far bigger economic relationship is East-West.

As Mrs Foster said, to make that observation is not to dismiss North-South, but merely to put it in its context.

While Boris Johnson is less weak as prime minister than his predecessor, Theresa May, her acceptance of the backstop in 2017 and attempt to put it in law, without even the Stormont lock, has made it the baseline for all further EU talks.

There is little sign of Dublin or Brussels climbing down, which leaves open the possibility that the government will try to force through a barely revised variety of the backstop, because it has run out of options.

This would be madness, and a massive UK strategic error. It would lead to a permanent Irish Sea border.

Mrs Foster is rightly trying to be flexible and yesterday said that the DUP would “look at” a time-limited backstop.

But there are real risks that even that would in effect be permanent, because once a backstop of any form was in law — that NI can never diverge from the EU in regulations or customs — Brussels and Dublin would never accept a trade relationship that had any other outcome. A time limited backstop might be as permanent as an open ended one.