Boris Johnson has appointed a former Treasury official as his Downing Street chief of staff.

Dan Rosenfield will begin working in No 10 next month before he formally takes over from acting chief of staff, Lord Udny-Lister, in the new year, Downing Street said.

The move comes after a row over a proposal to appoint No 10 communications chief Lee Cain to the post led to Mr Cain and his close ally Dominic Cummings both leaving Downing Street.

Dan Rosenfield
Dan Rosenfield has appointed as his Downing Street chief of staff (Jack Ladenburg/Hakluyt/PA)

Mr Rosenfield joins No 10 from Hakluyt – a strategic advisory firm for businesses and investors – where he has been global head of corporate clients and head of the UK business since 2016.

He had previously worked as a Treasury official for over a decade, serving as principal private secretary to chancellors Alistair Darling and George Osborne.

He is also chairman of World Jewish Relief, the British Jewish community’s humanitarian agency.

The departure of Mr Cummings and Mr Cain was widely seen as the culmination of a bitter internal power struggle in which the former Vote Leave campaigners had sought to strengthen their grip on No 10.

Dominic Cumming and Lee Cain
Dominic Cummings, left, and Lee Cain were previous key advisors in Downing Street (PA)

Mr Cain’s appointment to the chief of staff post – in which he would have been one of just a handful of people in Downing Street with direct access to the Prime Minister – was said to have been opposed by Mr Johnson’s fiancee Carrie Symonds.

Allegra Stratton, the Prime Minister’s press secretary, was also reported to have advised against giving him the role.

The departure of Mr Cummings – who made no secret of his contempt for most MPs – was widely welcomed by many Tories at Westminster.

Senior Conservatives had been urging Mr Johnson to appoint a chief of staff who could build bridges with the parliamentary party.

The feeling that MPs had been routinely ignored by No 10 was seen to have fuelled a recent series of damaging Commons rebellions.

Boris Johnson’s fiancee Carrie Symonds was said to have opposed Mr Cain’s appointment as chief of staff (Victoria Jones/PA)

They will hope that Mr Rosenfield’s arrival will see the start of Mr Johnson’s much-heralded Government “reset” with the adoption of a more inclusive approach.

He is expected to spend his first weeks in Downing Street meeting with ministers, Conservative MPs and the wider No 10 team.

His previous employers, Hakluyt, have a reputation for discretion, having been founded by former MI6 officers, and are reported to maintain a close relationship with the intelligence agencies.

Mr Rosenfield’s appointment was welcomed by Mr Osborne’s former chief of staff, Rupert Harrison, who worked with him in the Treasury.

“Dan is a class act and an inspired appointment,” he tweeted.

“He was the principal private secretary in the chancellor’s office who managed the transition from Alistair Darling to George Osborne.

“Bright, tough and politically savvy with a small ‘p’.”

Former Treasury minister David Gauke, one of the pro-Remainers purged from the Tory Party by Boris Johnson, agreed he was a sensible choice.

“I’m probably not doing him any favours in saying this but Dan Rosenfield is smart, likeable and effective. This should be a good appointment,” he tweeted.