Boris Johnson becoming Tory leader again would condemn the party to a decade in opposition, David Davis has warned.
The former Brexit secretary said the mounting speculation that the former prime minister could make a comeback “is corroding the party’s chances at the next election”.
Johnson supporters have been talking up his chances of a Downing Street return as the Tories continue to languish behind Labour in the polls.
But Davis - who famously told Johnson to resign as PM in the Commons a year ago - said the Conservatives would face a 1997-style landslide defeat if the former PM came back.
Writing in The Independent, he said: ”Boris is not going to be the electoral asset that his acolytes claim.
“The continual drumbeat calling for his return is certainly going to fail, but in the process it is corroding the party’s chances at the next election.
“Continually driving a message of division into the public domain, continually undermining the current leadership, will do nothing but harm.
“What’s more, in 1997 many of those who were the most vocal critics of the then government were the ones who got the worst results, thrown out on their ear in the electoral response to their own antagonisms.
“It is entirely within the reach of a quietly competent Sunak government to win re-election.
“But if Boris’s foolish pipe dream of a resurrection continues, the same will happen again – and more importantly, we will be out of power for a decade once more.”
Johnson, who resigned as prime minister last year in the wake of the partygate and Chris Pincher scandals, made a brief comeback attempt following Liz Truss’s demise in October.
He eventually decided to pull out of the race to succeed her, but has insisted he will stand for re-election at the next election.
Davis’s comments once again expose the deep divisions within the Tory Party less than two years out from the next election.
Rishi Sunak is already coming under massive pressure from his MPs barely three months after becoming PM.
He was this week forced into another humiliating climbdown over the online safety bill after a rebellion by more than 50 Tory backbenchers.
Sunak has also performed U-turns on housebuilding targets and onshore wind farms under pressure from his MPs.