He then listed his likely successors. Mr Kedjanyi added: “In terms of a likely successor, Angela Rayner is the big story – the former Deputy PM has firmed up at the head of the market and is now 9/4 to replace Starmer (from 13/5), with Ed Miliband also shortening to 6/1 (from 13/2). Conversely, Wes Streeting (11/2) is on the drift.

“Andy Burnham’s opportunity to replace Starmer may well have passed, since being blocked from standing in the Gorton and Denton by-election, but he remains in contention at 10/1 (from 12/1).”

The odds specialist also mentioned Alistair Cairns as one to watch. Now at 12/1 from 40/1, the MP is the biggest mover from the past two weeks.

It comes as Scottish Labour leader Anas Sarwar has told how it caused him “personal hurt and pain” to call for his “friend” Sir Sir Keir to step aside as Prime Minister earlier today.

At a press conference in Glasgow on Monday, Mr Sarwar declared there have been “too many mistakes” in Downing Street and called for the PM to quit.

Scottish Labour MP, and UK Government minister Ian Murray insisted that Mr Sarwar was “wrong” to call for the PM to step down.

Posting on social media, Mr Murray said: “The last thing we need is more chaos when the public want a govt on their side tackling the cost of living.

“We inherited a badly failing economy & public services. That takes time to turn around & Keir deserves that time.

“I’m sorry & deeply disappointed that Anas is wrong here.”

Sir Keir’s Cabinet has also come to his defence.

A Downing Street spokesperson said: “Keir Starmer is one of only four Labour leaders ever to have won a general election.

“He has a clear five-year mandate from the British people to deliver change, and that is what he will do.”