BRUSSELS has shot down the UK’s chaotic “backstop” plan to prevent a hard-border in Ireland.

The proposal, published yesterday after much infighting among the Tories, suggested that if the government couldn’t agree a future relationship with Europe before Brexit day in March 2019, then the UK would “temporarily” match EU trade tariffs and regulations until 2021.

Initially the Prime Minister had wanted it open ended, with no stop date, but David Davis had threatened to resign as Brexit secretary unless Theresa May included a time limit.

Tory Brexiteers were fearful that without an end date the backstop, could become the permanent position.

The fighting in London was watched with bemusement in Brussels.

The backstop, which takes its name from the net used in baseball to catch balls missed by the batter, is supposed to be a contingency plan, used only if all negotiations about “tariffs, quotas, rules of origin and customs processes including declarations on all UK-EU trade” fails.

But with little agreement in cabinet over the two options to replace the UK’s membership of the customs, this safety net is becoming increasingly more likely. Europe’s chief Brexit negotiator Michel Barnier welcomed the proposal but said the EU would look at it with three pertinent questions in mind: “Is it a workable solution to avoid a hard border? Does it respect the integrity of the [Single market/customs union]? Is it an all-weather backstop?”

The EU parliament’s Brexit negotiator, Guy Verhofstadt said it was “difficult to see” how the government’s proposals would “deliver a workable solution to avoid a hard border” and respect the integrity of the single market and customs union.

“A backstop that is temporary is not a backstop, unless the definitive arrangement is the same as the backstop,” he tweeted.

The EU had initially proposed a backstop that would see the island of Ireland keep the same regulations and tariffs as the rest of Europe. The Tories said this effectively plonked a border in the middle of the Irish sea and would simply not do.

Though the inclusion of any date in the proposal is a win for Davis, the exact wording of the proposal was not quite as strong as he’d hoped.

The “temporary customs arrangement”, if it is needed, would be “strictly time-limited” as “the UK expects the future arrangement to be in place buy the end of December 2021 at the latest”. There was some suggestion the “expects” in that sentence gave May some wriggle room.

Earlier in the day, David Jones, a former Brexit minister, speaking on BBC Radio 4’s Today programme said May refusing to capitulate to Davis would be catastrophic for her: “We need to make sure that David Davis stays at the negotiating table. Anything that caused him to leave would be deeply regrettable and deeply damaging to the country.”

Jones said that the proposal as it stood would not be acceptable to the “mass” of the Tory Party.

“It would tie us effectively into the EU’s customs arrangement for an indefinite period,” he said. “It would be the Hotel California scenario — we’d have checked out but we wouldn’t have left.”

The SNP’s Brexit spokesman called the government’s proposal a “political cop out, aimed at nothing other than trying to hold the Tory party together.”

He added: “Leaving the EU will have a devastating impact on jobs and the economy and an impact on each and everyone one of us. Yet instead of tackling what is clearly becoming a crisis – the Tories are only interested in the crisis that is enveloping their political party.”

Those comments were echoed by Labour MP Hilary Benn, who chairs the Westminster Brexit committee, who described the proposal as a “half a backstop”.

“On time-limiting the backstop, the proposal makes it clear that it will last as long as it takes to bring in another system.

“And since ministers can’t say how long that will be, the backstop will be here to stay unless and until it is replaced by other arrangements that can also keep an open border in Northern Ireland.”