Backing Boris Johnson for prime minister again would be a “retrograde” step because he cannot form an effective government, trade minister Greg Hands has said.

It was not the partygate scandal which forced Mr Johnson to resign as PM in the summer, but the fact that more than 60 ministers and parliamentary private secretaries (PPS) had abandoned his government, according to Mr Hands.

He recalled that in the dying hours of leadership in July, Mr Johnson offered him the Northern Ireland secretary job “(a position not to be thrown around lightly), if I could just show the world he could indeed form a government”.

Boris Johnson resignation
Former prime minister Boris Johnson as he made his resignation statement outside 10 Downing Street (Gareth Fuller/PA)

He added: “I think he would have offered me almost anything. I refused.

“Indeed, as we sat there, more resignations of junior ministers, whips and PPSs were coming in.

“I told him he had to resign, as he couldn’t form a government. Doubtless others said the same. The next morning, he duly did resign.

“I have no reason to have any more confidence today that he could put together an effective government.”

He also tweeted: “68 members of the Govt had resigned in 24 hours – and more were coming. How could any of those 68 now serve, just weeks after? People forget quickly. I don’t.”

Mr Hands is once again backing former chancellor Rishi Sunak in the Conservative Party leadership race after he lost out last time to Liz Truss.

Commons Leader Penny Mordaunt is the only candidate who has so far officially declared she is running.

Mr Johnson is to face an inquiry into whether he lied to the Commons over the partygate scandal, for which he was fined by police.

If found guilty by the Commons Privileges Committee, he could face recall proceedings that would leave him battling for his seat in the Commons if he receives a suspension of 10 days or more.

His popularity with the public has crashed, even if he still rides high with the Tory membership.

Some MPs have even suggested they could resign the party whip if he wins.

Mr Hands tweeted: “I have no doubt at all that the best option is @RishiSunak. I have worked closely with him in government.

“He had the right policies in the summer, and he has the right policies now. He is the right person to get the UK through the tough economic times and therefore for us to have a good chance at the next election.

“I like Boris, but bringing him back would be retrograde. Why?

“What finally finished Boris on July 7 wasn’t the ‘parties’ or even the Privileges Committee – it was that he wasn’t able to form a Government.”