Brexit: Opposition parties give Labour until the end of the day to table no-confidence motion in Theresa May

Theresa May was forced to shelve a vote on her Brexit deal to avoid a catastrophic defeat

Opposition parties have told Jeremy Corbyn that he has until the end of the day to table a confidence motion in Theresa May.

SNP Westminster leader Ian Blackford issued the Labour leader with an ultimatum, saying he must act before close of play on Tuesday or other parties would be forced to intervene.

Mr Corbyn is facing growing pressure to put forward a no-confidence motion in the government after the prime minister was forced to pull a vote on her Brexit deal at the eleventh hour to avoid a catastrophic defeat at the hands of Tory backbenchers.

Labour is keen to trigger an early general election but the party has so far held back from trying to topple the government, saying it will put forward a motion when it is “most likely to be successful”.

Shadow Brexit minister Jenny Chapman had to perform a frantic U-turn after she initially claimed that Labour would act before Christmas. She then tweeted shortly afterwards that she had “got a bit carried away” making a festive joke.

Parliamentary leaders from the other opposition parties wrote a letter to Mr Corbyn, saying there is an “overwhelming” case for a confidence motion following Ms May’s decision to defer the crunch Commons vote on her Brexit deal.

Speaking at a press conference in London, Mr Blackford said Britain was facing a “constitutional crisis unparalleled in modern times” and suggested that his party, the Greens, the Liberal Democrats and Plaid Cymru could attempt to force a vote in the government if Labour doesn’t.

Pressed again by The Independent, he said: “I think Jeremy has until the close of business today.”

Mr Blackford said: “Our message to Jeremy Corbyn is all of us have to work together to move that motion of no confidence and I appeal to Jeremy to do that.

“But all of us working together have to accept our responsibilities, and if Jeremy can’t do it himself in that position, then we as the leaders of the other opposition parties must rise to that challenge and we must lay down that motion of no-confidence in the prime minister.”

Prominent Tory backbencher Anna Soubry also backed the calls, stating: “The biggest obstacle to a People’s Vote at the moment is Jeremy Corbyn.

“If not now, when, Jeremy? He has got to start this process now.”

The politicians who wrote to Mr Corbyn also appealed to the government to begin drawing up the necessary legislation for a new vote, ensuring that parliament can be given the time to debate the question and the date of the vote.

The group also called on the EU to extend Article 50 timetable to allow time to prepare for a second referendum.

Labour’s shadow chancellor John McDonnell said the SNP were wrong to believe they could table a vote of no confidence – insisting only the official opposition could do so.

He said Labour was making a judgement “day by day” when to act, telling reporters: “We will put one down when we can win it.”

Mr McDonnell denied that meant waiting until after a defeat of the prime minister’s deal, in a vote that might not happen until 21 January, but added: “Never ask a question until you know the answer.”

He also accused the SNP of hoping to force a no-confidence vote now to wreck Labour’s chances of securing a general election, because it was “terrified” of losing to Labour in Scotland.

Mr McDonnell accepted that his party could attempt to table several no-confidence motions – as the Conservatives did to destabilise Labour in the 1970s – but said the speaker could refuse to allow them, if one had already been lost.

Unite boss Len McCluskey also waded into the row, saying: “Jeremy Corbyn should not be bounced by those with little or no interest in seeing Labour elected.

“They would be better placed using a censure motion and waiting for the right time to issue a vote of no confidence.”

The prime minister is currently on a whistle-stop tour of European capitals, appealing to allies such as Dutch prime minister Mark Rutte and Angela Merkel, the German chancellor, to offer concessions to get her deal through parliament.

Downing Street announced that Ms May would bring the deal back to parliament by 21 January, a delay of more than a month of the much-anticipated “meaningful vote”.