The return of Boris Johnson as prime minister would be "suicidal" for the Conservative Party, one of its MPs has said.
Johnson's supporters are reportedly planning to force a vote of no confidence in the incoming prime minister.
But they have been warned from within their own party that such a move would have a damaging effect on the Conservatives.
One of the two remaining candidates in the Tory leadership race, either Liz Truss or Rishi Sunak, will be named new Tory leader at lunchtime on Monday.
Watch: How Boris Johnson's time as PM compares to his predecessors
Truss is widely expected to be named leader and officially become prime minister on Tuesday, when Johnson will visit the Queen in Balmoral to formally step down.
The Sunday Mirror reported at the weekend that 12 MPs are willing to submit letters to the party's 1922 Committee to express no confidence in the incoming prime minister, in a desperate effort to spark a campaign to reinstate Johnson.
But The Times reported on Monday that one MP said any such move would destroy the party.
Jake Berry, the MP for Rossendale and Darwen in Lancashire, told Times Radio: "It's certainly suicidal."
Lord Udny-Lister, Johnson’s former chief of staff, told Sky News the outgoing prime minister will be “very sad” as he travels to Balmoral to formally offer his resignation to the Queen.
But he also said he would “never say never” about a return for Johnson.
“He is going to be watching all this and if something happens in the future, as you said, the ball comes loose in the scrum, then anything can happen," he said.
“I’m not going to predict. All I’m saying is, I would never write him off.”
However, the former Conservative chancellor Lord Hammond dismissed as “fantasy” the notion that Johnson could mount a political comeback, warning him not to linger over the new government like a “malevolent shadow”.
He told Sky News on Sunday that “Boris has not been a good prime minister”.
He added: “He needs to let the new prime minister get on with his or her job and make it clear that he’s moved on as well.”
Labour's Nick Thomas-Symonds, the shadow international trade secretary, told Sophy Ridge on Sunday on Sky News: “It really does show the depths to which the Conservative Party has sunk and the fact they are so tired after 12 years in office.
“They’ve just ousted a leader after his flagrant disregard for COVID rules, after he showed, time and again, it was one rule for him and another rule for the rest of the population.
“It really does show now the Conservative Party has completely lost its way if they are saying credibly that they want to get rid of one leader, then try to have a leadership contest with others, then try and bring the other leader back.”
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