His intervention cames as Tory rebels switched their attention to the Conservative whipping operation and accused whips of “blackmail” over “partygate”.

William Wragg MP, a vocal critic of Mr Johnson, suggested police could be called in to deal with allegations that MPs had been threatened with the removal of funds from their constituencies if they rebelled against the Prime Minister.

On Thursday night, sources in the whips’ office said the claims were a “load of b——-” and demanded to see “a single shred of evidence” for them.

Mr Johnson’s fate hangs in the balance ahead of the publication, as early as next week, of a report by the civil servant Sue Gray into claims of parties across Whitehall while the rest of England was adhering to Covid restrictions.

A vote of no confidence in Mr Johnson’s leadership will be triggered if more than 54 Conservative MPs submit letters to the head of the 1922 committee calling for one.  

Lord Marland was part of a team of friends and allies including Lord Udny-Lister and Sir Lynton Crosby who advised Mr Johnson both during his time as London Mayor and latterly in Parliament.

He said Mr Johnson’s concerns over “partygate” were not “terminal” and suggested he could win over the Tory party.

‘He’s got to develop the Brexit dividend’

“He has got to show that we are a more competitive economy than America and the European Union, which means getting a real onslaught on regulation and a low tax regime,” he said.

“He’s got to develop the Brexit dividend, which to date he hasn’t, and he’s going to cut out all this fluffy stuff like animal welfare sentience Bills and all these things, which actually may have interest but it just takes up a huge amount of parliamentary time when we’ve really got to get on with the big crisis in social care, energy.”

Lord Marland said “a lot depends on whether he wants to be” Prime Minister by the end of the year.

He said: “He’s quite used to being in these scrapes, and so some of it is self-inflicted. But he’s very good at getting out of them, and I just hope he’s got the power and the will to do it. Otherwise, I think the country will be in quite a lot of trouble.”

Lord Marland, a millionaire businessman who held ministerial posts in David Cameron’s government from 2010 to 2014, said he did not speak to Mr Johnson that much but had been exchanging messages “quite regularly recently”.

He added: “You’ve been through a shattering period and you must be thinking every day: ‘I can’t … This is a nightmare.’ I think we’ve just got to cut people a lot of slack and see where the thing goes.”