Labour won't hand Boris Johnson a "get out of jail free card" by supporting national unity government, says Rebecca Long-Bailey

Labour does not want to hand Boris Johnson a "get out of jail free card" by supporting a national unity government aimed at stopping a no-deal Brexit, Rebecca Long-Bailey has said.

The Shadow Business Secretary - a key ally of Jeremy Corbyn - warned that such a plan would not be able to muster a "clear majority" in the Commons if the Prime Minister is defeated in a confidence vote.

The proposal has been talked up by key Remain-backing figures, including former attorney general Dominic Grieve, in recent days.

He said a "number of people" - including former Labour frontbenchers - could head up a cross-party anti-Brexit administration if Johnson's government is brought down when Parliament returns next month.

"There’s nothing that the Prime Minister could do to prevent such an administration being formed if the majority of the House of Commons wanted it," Grieve said.

Senior Liberal Democrat Sir Ed Davey has also suggested that former Labour frontbenchers Yvette Cooper or Hilary Benn could head up such an administration.

But speaking to Channel 4 News, Long-Bailey appeared to sound the death knell for the plan.

She said: “We’re happy to collaborate on a cross-party basis, but we wouldn’t countenance a national government of unity, because we think that we need to have a clear majority for a government in Parliament, and that’s why we’re calling for a general election."

The Labour frontbencher added: "What we don’t want is a national unity government that gives Boris some sort of get out of jail free card, so as soon as Brexit’s been sorted out, he can sail back in without any problems at all, without a sufficient Parliamentary majority. That simply wouldn’t be right."

Shadow Chancellor John McDonnell on Tuesday night said Labour would table a motion of no confidence in Johnson "fairly soon" after Parliament returned from its summer break on 4 September.

But he also insisted that any government formed if Johnson is defeated "would be a Labour government" aimed at stopping a no-deal Brexit because the party "wouldn’t enter into coalitions or pacts".

Speaking at the Edinburgh Fringe, he told broadcaster Iain Dale: "Why does it have to be a Labour government? Because that is the way that we will get the bulk of the support behind us in terms of the Parliamentary Labour Party.

"You’ve got a number of Conservative MPs on the backbenches now who will do anything they possibly can to prevent a no-deal."

The comments came as it was reported that Remain-supporting MPs are considering asking the Queen to sack Johnson if he refuses to step down after losing a confidence vote.

According to The Telegraph, MPs are exploiting using a parliamentary procedure known as a Humble Address to ask the Queen to write to the Prime Minister to dismiss him from office if he loses such a vote.

One MP told the paper: "The Queen would write him a letter saying he is dismissed. She would have to sack him. Of course, she would."

The move follows a bitter row over claims that Mr Johnson would try to stay on in Number 10 to push through Brexit regardless of the outcome of any confidence vote.

Grieve branded that position "breathtaking, stupid" and "infantile".