Boris Johnson is expected to make further changes to his Downing Street operation as he tries to maintain his grip on power.

The Prime Minister made new appointments over the weekend, with Chancellor of the Duchy of Lancaster Steve Barclay becoming his chief of staff and journalist and former aide Guto Harri returning as his head of communications.

The Times reported No 10 was hoping to announce the return of Dame Emily Lawson as the new permanent secretary this week.

Dame Emily, who currently runs NHS England’s vaccination programme, was seconded to Downing Street’s delivery unit – a team in charge of ensuring the Government delivers on its policies – in April last year before returning to the health service in October.

Senior backbencher Tom Tugendhat, a potential leadership candidate if Mr Johnson is forced out, said the Prime Minister’s future depends on how the “reset” goes.

The changes come after a swathe of resignations from among the Prime Minister’s aides.

The beleaguered leader was left wounded by the so-called partygate saga – with the police investigation still hanging over his head – and his refusal to apologise for a slur made against Sir Keir Starmer over the failure to prosecute Jimmy Savile.

The acute issues built on longer-term concerns from MPs over the rising cost of living, a looming hike in National Insurance, a series of sleaze allegations and the general running of the No 10 operation.

Mr Tugendhat said: “I think the Prime Minister has just done his reset. Let’s see what Number 10 brings out because there’s an awful lot of talent going in, as you know, there’s an awful lot of talent coming out, and let’s see what changes are.

“I mean this is a decision clearly for 360 or so Members of Parliament and let’s see where it goes to, but I think the point remains that we’ve got to be looking at the future, we’ve got to be looking at what’s best for the British people and focus absolutely on how we achieve the results that we really need for this country.”

Asked if what he described as a “personal psychodrama” could finish with an end to the Prime Minister’s leadership, Mr Tugendhat said: “Well it depends how the reset goes. Going into a leadership election is hardly ending a psychodrama”.

Mr Barclay’s new responsibilities are expected to result in some of his ministerial duties being reallocated, with a limited reshuffle also widely expected to see Mark Spencer moved from his post as Chief Whip as Mr Johnson seeks to rebuild bridges with his MPs.

Some 15 Tory MPs have now publicly called for Mr Johnson to resign but not all have sent letters of no confidence to 1922 Committee chairman Sir Graham Brady, although the true total of Conservatives who have turned against the Prime Minister may be far higher.

The total number of letters submitted is a closely guarded secret but if 54 are received by Sir Graham a no confidence vote would be triggered.

Health Secretary Sajid Javid told Sky News: “I don’t think there is going to be a leadership election.

“We have got a leader in place who is doing an excellent job, is getting on with the job, is delivering on the commitments that we made, and I am there to support him, along with the rest of us.”

Mr Javid also defended Carrie Johnson, the Prime Minister’s wife, who has been the target of criticism over her perceived influence in No 10.

Mrs Johnson issued a rare public statement on Sunday insisting she “plays no role in Government” and has been targeted by “enemies” of the Prime Minister in a “brutal briefing campaign”.

The Prime Minister’s former aide Dominic Cummings has been one of Mrs Johnson’s most vocal critics, while a biography of the 33-year-old mother of two by Tory peer Lord Ashcroft has also put her role in the spotlight.

Lord Ashcroft, writing in the Mail, said his research had suggested her “behaviour is preventing him (Boris Johnson) from leading Britain as effectively as the voters deserve”.

Asked about the criticism of Mrs Johnson, Mr Javid said: “”I just think as a general rule, a politician’s partner – any politician, any party – should be off limits.

“It’s the politician that has chosen to have a public life… I think the, this whole focus on Carrie Johnson in some of these reports, I think it’s very undignified and very unfair.”