Theresa May is heading for emergency Brexit talks with German Chancellor Angela Merkel on Tuesday after leaving Westminster in turmoil.

The Prime Minister’s move to abandon a crunch Commons vote on her Brexit deal drew howls of condemnation from the opposition as well as a number of Tories.

Mrs May took the decision to pull the vote, scheduled for Tuesday, as the Prime Minister admitted to MPs she faced a “significant” defeat on her Brexit agenda.

The PM will also meet Dutch counterpart Mark Rutte in The Hague on Tuesday in a bid to gain reassurances on the exit deal from European leaders ahead of a crunch EU summit on Thursday.

Mrs May, who is facing repeated calls from leading Tory Brexiteers to be replaced as PM, was forced to abandon the Commons vote as the scale of opposition to the Brexit deal, especially regarding proposed backstop arrangements for the Irish border, threatened a crushing rejection of her plans.

As anger at Westminster continued to fester over the PM’s move to cancel the Brexit vote, MPs were poised for an emergency debate on the situation on Tuesday.

International Trade Secretary Liam Fox said it would be difficult to get the Brexit deal through Parliament without reassurances the UK would not be “trapped” in backstop measures ensuring no return to hard border in Ireland.

The backstop would see the UK obey EU customs rules after a transition period if a wider trade deal has not been agreed with the EU by then.

Referring to Mrs May’s lobbying mission in Europe, Dr Fox told BBC2’s Newsnight:  “My colleagues will want to see that their fears of being trapped in a backstop cannot be realised.

“Without the ability to genuinely reassure my colleagues that they could not legally be kept in the backstop against their will, it will be difficult to get this through the House of Commons.”

He added: “Can we find a way of giving both sides the reassurances they seek?

“Are there other ways of achieving the actual backstop itself?

“There is no clear majority in Parliament for anything other than the current deal, with changes to the backstop.

“It seems to me this is the only thing that would be able to get through the House of Commons.

“If we can’t get changes to the backstop that may not be possible.

“In which case MPs, whether they were Leave or Remain, will have to confront that there is then only one of two options; no Brexit, or no deal.”

However, European Council president Donald Tusk insisted there was no question of reopening negotiations on the Brexit deal.

With Jeremy Corbyn under pressure from a significant number of MPs and Peers to force a confidence vote on the Government, Labour former Cabinet minister Lord Mandelson said the opposition had not laid a glove on the Government.

He told the BBC: “I think the Labour Party, the Labour leadership, is facing a bit of a dilemma.

“I mean, they want to straddle, and retain the support of the third of Labour voters who backed Leave in 2016, and the two thirds of Labour voters who backed Remain.

“Well, what happens when you, you know, ride two horses like that, you end up doing the splits.”

He added: “I think people don’t understand. Why didn’t the Labour Party come out with real bite and lay a glove on what is an absolutely shambolic Government?

“The only people that the Tory party and the Government don’t fear is the opposition front bench, because they are not laying a glove on them.”

Meanwhile, Tory former prime minister David Cameron has said he has no regrets about calling the Brexit referendum – despite previously warning that leaving the European Union would be an “act of economic and political self-harm”.

Approached by Sky News while getting into his car, he said: “I don’t regret calling a referendum. I made a promise in the election to call a referendum and I called the referendum.

“Obviously I’m very concerned about what’s happening today but I do support the Prime Minister in her efforts to try and have a close partnership with the European Union.

“That’s the right thing to do and she has my support.”

The usual Tuesday Cabinet meeting will be held later in the week due to Mrs May’s travel plans, Downing Street said.