Boris Johnson ramped up the odds of a No Deal Brexit last night by ruling out what could have been a crucial compromise.
The PM hopeful is accused of "moving the goalposts" after he refused to accept any form of - the clause which made Theresa May's Brexit deal crash and burn.
The backstop would force the UK to follow EU customs rules in order to avoid a hard border between Northern Ireland and the Republic.
Tory MPs had suggested they were willing to back the Brexit deal if there was a time limit or "exit mechanism" in the backstop.
Even this would have been a big ask from the EU, which refused to agree either in talks with Theresa May .
But now Mr Johnson has declared even that compromise, if agreed, would not be enough.
He told a debate last night: "I’m not attracted to time limits or unilateral escape hatches or all these elaborate devices, glosses, codicils and so on that you could apply to the backstop."
A Tory MP warned the comments were "worrying and depressing" and said he hoped they would be withdrawn.
The EU has said it is not prepared to renegotiate the withdrawal deal, which includes the crucial backstop clause.
But both Jeremy Hunt and Boris Johnson are promising to do so, and want to take Britain out of the EU by the deadline of October 31.
Mr Hunt also disowned the backstop last night saying: "The backstop, as it is, is dead ... I don’t think tweaking it with a time limit will do the trick, we’ve got to find a new way.”
Such a hardline approach could prompt Remainer MPs to vote no confidence in the government - prompting a general election.
Simon Hoare, chairman of the Northern Ireland Affairs Committee, said Mr Johnson's comments were "worrying and depressing".
Accusing both candidates of "moving the goalposts", the Tory MP told Sky News: "Even the most diehard of my Brexit supporting colleagues were talking about a time limit, end date, unilateral exit mechanism.
"Either of those would have been very challenging to deliver. But now it seems we've gone the Full Monty on this and gone for 'there should be no backstop at all.'"
He added: "All I can hope is this is prose caught up in the heat of an election campaign and whoever wins, reality will dawn and such talk very quickly disappeared."
It came as the woman set to become the next head of the EU has announced she's willing to back a third delay to Brexit.
In her confirmation speech to the European Parliament, Ursula von der Leyen said she will back postponing Britain leaving the EU beyond October 31 if there's a "good reason".
And she said: "In any case the UK will remain our ally, our partner and our friend."
Ms von der Leyen is standing to be the President of the European Commission, the body which has led Brexit negotiations with the UK. Although this would give her influence, any decision to offer a delay would be up to the 27 other EU countries' national leaders in the European Council.
