Boris Johnson has suggested the Conservatives had an “outbreak of irrationality” when he quit as leader.

The former prime minister said his party made the “wrong calculation” when he was “kick(ed)” out as leader in July 2022 following a raft of ministerial resignations.

Mr Johnson has undertaken a series of interviews to mark the publication of his book Unleashed, which comes out next week.

Speaking to GB News in an interview that was broadcast on Sunday, Mr Johnson was asked why he was no longer in Number 10, given that his party were now in opposition despite winning a majority of 80 in 2019.

“I think the answer to that, sadly, is that there was an outbreak of irrationality in my party, and I think they made the wrong calculation,” he said.

Pointing to things he achieved in office, including the vaccine roll-out, Mr Johnson added: “If you ask me, if you really push me to say, was it all a terrible mistake to kick me out? Yes, I think it was and I think it was a goof.”

Mr Johnson announced he was quitting as prime minister and Conservative leader in the wake of the partygate and Chris Pincher scandals.

His announcement followed a series of mass ministerial resignations, including by now-Tory leader Rishi Sunak, over a period of several days, as the support of the parliamentary party ebbed away.

In the book, due to be released on Thursday, Mr Johnson retracted his apology for the partygate scandal that contributed to his political downfall.

He wrote that he made a “mistake” in offering “pathetic” and “grovelling” statements over the lockdown-era gatherings in Downing Street that sparked a public outcry and dealt a major blow to his premiership.

Challenged on his change of tone in an ITV News interview on Friday, Mr Johnson said: “What I was trying to say there was, I think that the blanket apology – the sort of apology I issued right at the beginning – I think the trouble with it was that afterwards, all the accusations that then rained down on officials who’d been working very hard in Number 10 and elsewhere were thought to be true.”

He added: “You can’t say that I haven’t been exposed over the last few years to the full force of people’s anger and indignation.”