Jonathan Powell, who was the chief of staff to Tony Blair, said it “all seems a bit desperate” as he questioned who would pay his chief of staff salary and if it would count against his taxpayer-funded ministerial wages

A government source said Mr Barclay would have desks in No 10 and the Cabinet office, and that many of his current ministerial responsibilities will be redistributed to other ministers within the Cabinet office. He will, however, continue to chair Cabinet committees and lead the department.

Unlike Dan Rosenfield, his predecessor as chief of staff and one of five resignations from No 10 last week, the source said Mr Barclay will not be paid as a special adviser but via his ministerial salary. Whether he will get any uplift for the extra responsibility is to be “worked through,” said a source.

Role could be supported by permanent secretary

His role could be supported by the appointment this week of a permanent secretary to head the new Office of the Prime Minister, along with a new parliamentary private secretary (PPS) to Boris Johnson to replace Andrew Griffiths, another MP who has been brought in to head No 10’s policy unit.

A government spokesman said: “The Chief of Staff role will focus primarily on driving the Government’s agenda and ensuring it is better aligned with Cabinet and backbenchers.

“In his dual role as Chancellor of the Duchy of Lancaster and Chief of Staff, alongside his extensive experience as an MP, Steve Barclay will be well placed to ensure the Prime Minister’s levelling up agenda is delivered at maximum speed while strengthening Cabinet government and providing an enhanced role for Ministers and Parliament.”

Two names speculated as contenders for the No 10 permanent secretary role are Charles Roxborough, number two at the Treasury, and Sarah Healey, the permanent secretary at Culture who raised eyebrows by lauding the benefits of Peloton riding while working from home.

It emerged last week that Antonia Romeo, the Ministry of Justice’s top civil servant, turned down the permanent secretary role.

The Government rejected claims that Guto Harri, the new director of communications, was on six-month leave of absence from his work at Hawthorn Advisers, in case the No 10 role was not long term. Mr Harri, former BBC presenter, worked with Mr Johnson when he was London mayor.

“Guto Harri has resigned from Hawthorn Advisers. As with all Special Advisers, he will serve in his role for as long as the PM asks him to,” said a source. They declined to say if he would be paid more than his predecessor.

Mr Johnson is in talks to appoint David Canzini, a protege of Sir Lynton Crosby, the Australian election guru, who is advising the Prime Minister behind the scenes. They are understood to want a wider cull of other aides who have clashed with MPs and ministers before committing to a formal role.