Boris Johnson is party's 'greatest asset in modern times', says Jacob Rees-Mogg

Watch: Jacob Rees-Mogg says Boris Johnson will stand as Tory leader

Boris Johnson still has a solid mandate to lead the country despite being ousted by his own party a few months ago, his key ally Jacob Rees-Mogg said.

The former prime minister has not officially declared his bid to become Tory leader, but is expected to do so imminently.

He cut off his Caribbean holiday to return to the UK this weekend and is thought to have messaged a supporter on WhatsApp, saying: “We are going to do this. I’m up for it.”

Johnson and leadership rival Rishi Sunak held talks late on Saturday night, fuelling speculation they could strike a deal for a joint ticket.

But after the former chancellor officially announced his bid on Sunday morning, Johnson is expected to go head-to-head with him in the contest – which could finish late next week.

Some Tory MPs are very excited by the prospect of his comeback, arguing that he secured a solid majority in the 2019 election, but others fear he will send the party into a “death spiral”.

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After being forced to resign in early July amid a mass exodus of ministers over his handling of the Chris Pincher and Partygate scandals, many say he’s had his chance and that the party must move on.

But Rees-Mogg believes that Johnson still has what it takes, telling the BBC's Sunday with Laura Kuenssberg show: “Boris delivered Brexit, he supported Ukraine in standing up to Russia - he was the first world leader to do that – and he got us through a pandemic.

“He won a majority of 80 and he won Hartlepool in the by-election, he has been the greatest local asset the Conservative Party has had in modern times, and if you look at the poll in the Mail on Sunday today, he’s the one who appeals the most to people who voted Conservative in 2019.”

The business secretary added: “I think that’s such an extraordinary re-writing of history, to dismiss those achievements of historic proportions.

“He took over a Conservative Party that was 30% behind in the opinion polls in 2019 and within a few months won a majority of 80, that is a quite extraordinary electoral asset.”

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Rees-Mogg suggested the Labour Party’s calls for a general election to put a stop to ever-changing Tory leadership is “pretty hollow” considering the mandate Johnson secured.

However, since 2019 the former Tory leader’s credibility has been damaged after he was found to have broken his own rules on social distancing during the pandemic.

Numerous reports of politicians and civil servants attending lockdown-busting parties in what came to be known as “Partygate” led to widespread resentment among the public as people made great sacrifices during the outbreak.

Johnson managed to cling to power at the height of the scandal, but he was eventually forced to resign after he misled the public over his handling of the Pincher groping allegations.

The then-PM said he couldn’t recall misconduct allegations against Pincher, and after No 10 changed its stance a few times, it emerged he was aware of them when he appointed him as deputy chief whip.

Also standing in the contest is former defence secretary Penny Mordaunt, who is pitching herself as a unity candidate who can bring together a bitterly divided Conservative Party.

She told Kuenssberg: “People are fed up of the factional rows, the focus on ourselves.

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“We have got to remember why we came to this place in the first place, it was to serve our constituents and our communities.”

Mordaunt said reports that she was prepared to pledge her support for Johnson in exchange for a cabinet job are “completely false”.

Whoever becomes next Tory leader will face a challenge in restoring the party’s credibility following Liz Truss’ exceptionally brief spell in office.

Truss announced her resignation on Thursday after just 44 days as leader, making her the shortest running prime minister in British history.

Her proposed package of £45 billion in tax cuts – mainly benefiting the wealthy and funded by public borrowing – sent investors into a panic, sent the pound crashing, and were at odds with the Bank of England’s attempts to control inflation.

She sacked Kwasi Kwarteng, and his successor tore most of her programme to shreds, and despite clinging onto power for a few more days, her credibility was too damaged for her to stay on.

The Labour Party has no power to force a general election, but its leader Sir Keir Starmer appealed for the Tories to call one, saying the can "either put their party first or their country first".