Sir Keir Starmer has appointed one of Labour’s rising stars to a new role at the heart of Government, in a shake-up of his Downing Street operation as MPs return from their summer break.

Darren Jones will be chief secretary to the Prime Minister, a new ministerial role in which he will attend Cabinet.

Mr Jones, who had been chief secretary to the Treasury, will be based at No 10 and “directly oversee work across Government to support the delivery of the Prime Minister’s priorities”, Downing Street said.

Treasury minister James Murray will replace him as Treasury chief secretary, effectively acting as Chancellor Rachel Reeves'sdeputy.

Chipping Barnet MP Dan Tomlinson has replaced Mr Murray as Treasury exchequer secretary.

The appointment follows Sir Keir’s recruitment of Baroness Minouche Shafik, an economist and former president of Columbia University in New York, as his chief economic adviser.

Lady Shafik’s recruitment is part of a move to build economic expertise within the Government ahead of the budget this autumn, when Ms Reeves is expected to have to make tough tax and spending decisions.

The new adviser has also been deputy governor of the Bank of England and permanent secretary at the Department for International Development, a now-scrapped Government department.

Last week Sir Keir moved to replace the top civil servant in his No 10 team after less than a year in the post.

Nin Pandit, the Prime Minister’s principal private secretary, will take on a new post in September leading on the delivery of key priorities in No 10.

It marked the third high-profile departure from No 10 in less than a year, after the exit of chief of staff Sue Gray and communications director Matthew Doyle.

There have been rumours that junior ministers would face a reshuffle once MPs returned from their summer recess.

However, Government insiders have said no reshuffle will take place, at least in the first week of September.

Meanwhile Starmer has suffered another major personnel blow on Monday when his top spin doctor dramatically quit less than one year into the job. James Lyons’ departure was announced this morning, coming just days after the Prime Minister dismissed one of his most senior civil servants.