Angela Rayner has moved to block Sir Sadiq Khan from running for Parliament while he is London Mayor. The Deputy Prime Minister has tabled a Bill that would prevent anyone from serving as a mayor and an MP at the same time.

It would make the prospect of him winning a Commons seat before the next general election unlikely. Ms Rayner's department insisted the change is to ensure mayors can “focus on” serving their local populations.

A Tory strategist claimed the Ashton-under-Lyne MP was manoeuvring against rivals for the Labour leadership.

They told The Telegraph: “Fresh out of trying to do in Wes Streeting, yet again Angela Rayner is on manoeuvres, knifing potential leadership rivals.

“She should focus on delivering for Britain rather than on her petty party political squabbles. Yet again it’s party first, country last.”

Sir Sadiq is serving a record third term as London Mayor after being re-elected in May last year.

The high-profile Labour politician was previously the MP for Tooting from 2005 until 2016.

Sir Sadiq last year insisted he had “no interest at all to be a Labour leader or the next Labour leader” and “no ambitions to go back to the Commons”.

Ms Rayner has also been accused of trying to derail Health Secretary Wes Streeting's leadership chances.

She is scrapping a ban on organisations being registered as a campaign group and a political party at the same time which could benefit pro-Gaza candidates.

Mr Streeting won his Ilford North seat with a wafer-thin majority of 528 votes over a pro-Palestine candidate at the last election.

A spokesman for Ms Rayner's department said: “It is already the case that mayors who are police and crime commissioners cannot also serve as MPs, and these changes will make this consistent for all mayors so that they can focus on what is a significant role at the forefront of delivering change.”