Boris Johnson is “hoping to do a Berlusconi” and make a “populist return” to Downing Street after being ousted by his own MPs, according to a former Conservative cabinet minister.

In an interview with the Guardian, Rory Stewart said people needed to be reminded Johnson was forced to quit – over a slew of scandals – because some supporters wanted Johnson to “come back”.

Several of Johnson’s allies believe his detractors will come to rue removing him from office upon his successor taking over, and will brush off the poor polling as midterm blues.

But some Conservative MPs have privately voiced concerns the party could be on course to lose the next general election, due in part to the damage wreaked by Johnson – evidenced by a string of byelection losses and not having held a poll lead since December 2021.

Stewart, who ran against Johnson in the Tory 2019 leadership election, called Johnson “dangerous” and said “there are people who want him back”.

He added: “I think we need to remind people why he left. He should have gone much, much earlier. What he did was deeply, deeply shameful – and dangerous.”

Stewart feared Johnson may attempt to return to frontbench politics and likened him to other deposed leaders, saying: “He’s trying to do an Imran Khan or a Berlusconi. He’s going to be hovering around, hoping for a populist return.”

The former Italian prime minister Silvio Berlusconi, 85, has announced his desire to return to politics in next month’s elections after a career mired in scandal, while the former Pakistani prime minister Imran Khan has set his sights on a comeback after losing a no-confidence vote earlier this year.

However, some of Johnson’s supporters are confident those who turned against him will regret it.

A former adviser to Johnson in No 10 said he may seek to emulate Churchill, who had two separate spells as prime minister.

“He agrees with most Tories that Liz is very likely to be a disaster,” the source said, speculating Truss could face a leadership challenge herself before the next election. “A refreshed and maybe more remorseful Boris providing optimism after much darkness might appeal to parliamentarians and members alike.”

The Conservative MP Michael Fabricant said: “I‘ve been talking about ‘buyers’ remorse’ – those ministers who bought into the argument that Boris must go – for some time now. This may increase in the months to come.”

A government source suggested Johnson would initially “focus on cultivating his international image rather than Westminster games”, but would not disappear from the domestic political scene completely.

“Even though he’ll be happier Liz is PM than Rishi, he’ll be desperate to return as PM and so long as that’s even the slightest possibility he’ll do whatever he can in aid of that is my bet,” they said.

However a despairing Johnson ally said there was “no point now having sellers’ remorse”.

“MPs who thought that we would have a nice and friendly leadership contest were deluded,” they said. “We could have a focused government led by Boris tackling the cost of living and the war in Ukraine. But instead they wring their hands when their colleagues say nasty things on Twitter.”

Johnson’s chance of another shot at the leadership could hinge on the privileges committee inquiry into whether he misled parliament by repeatedly denying Covid laws were broken during parties in Downing Street.

The seven-person committee has suffered the resignation of one Conservative MP over the summer, Laura Farris. She has to be formally removed from the position by a vote of the Commons when it returns.

Sources said it would be tough to find somebody to replace her who will not attract accusations of bias for any previous comments on Partygate. However, there are a handful of backbench Tory MPs who keep a low profile and have little social media presence who may be approached.