Jeremy Corbyn is facing demands from Labour MPs to call an immediate vote of no confidence in the Government following Theresa May’s decision to defer the Brexit vote.
More than 30 MPs, 15 peers and five MEPs have signed a letter urging the Labour leaders to table a vote this week.
If that fails, they say Labour must commit “straight away” to a second referendum, with an option to remain in the EU on the ballot paper.
Signatories to the letter, organised by former shadow cabinet member Ian Murray, include a number of prominent supporters of a so-called “people’s vote” including Chuka Umunna, Chris Leslie and Owen Smith.
“With the Government now clearly unable to command a majority in the House of Commons for the Prime Minister’s Brexit plan - which is at the heart of the Government’s entire agenda - it is imperative to take action this week under the terms of the Fixed-term Parliaments Act to table a vote of no confidence in HM Government,” the letter stated.
“If this fails we must commit to a public vote with an option to stay in the EU straight away.
“It is imperative that the country clearly knows where our Labour Party stands at this critical moment so now is the time to immediately take steps to move forward to a public vote.”
The letter echoes calls from other opposition parties - including the SNP and the Liberal Democrats - for Labour to move a no confidence motion.
The Labour leadership however, has been cautious about tabling a confidence motion, warning of the difficulties of forcing a general election under the terms of the Fixed-term Parliaments Act, originally passed by the coalition under David Cameron.
A Labour spokesman said: “We will put down a motion of no confidence when we judge it most likely to be successful.
“It is clear to us that Theresa May will not renegotiate the deal when she goes to Brussels, and will only be asking for reassurances from EU leaders.
“When she brings the same deal back to the House of Commons without significant changes, others across the House will be faced with that reality.
“At that point, she will have decisively and unquestionably lost the confidence of Parliament on the most important issue facing the country, and Parliament will be more likely to bring about the general election our country needs to end this damaging deadlock.”