Keir Starmer ‘will announce as early as Monday that he is quitting as Prime Minister’ after spending weekend locked in tense talks about his future with his wife Victoria at Chequers

Sir Keir Starmer will announce he will step down as Prime Minister as early as Monday, following Andy Burnham’s emphatic victory in the Makerfield byelection, it was claimed last night.

The Prime Minister was said to have concluded, after discussions with Cabinet colleagues, No 10 advisers, union leaders and major Labor donors, that his position was no longer tenable.

Sources insisted Sir Keir, who was discussing his future with wife Victoria in their hometown of Chequers this weekend, has not yet made a final decision.

But senior Labor figures told The Observer they believed a clear statement from the Prime Minister could come tomorrow or this week.

Last night Downing Street responded by insisting the position had not changed since Friday, when the Prime Minister vowed to continue fighting and said he would no longer run away from a challenge that Mr Burnham and possibly former Health Secretary Wes Streeting also awaited.

Sir Keir said at the time: ‘If there is a competition, yes I will run. I’ve said many times that I won’t give up on this.’

The Prime Minister will not ‘walk away’ from Downing Street and create a political vacuum, a Labor colleague has claimed. Instead he would ‘arrange for a slow march as a matter of duty and honour’.

Andy Burnham, who defeated Reform England in the Greater Manchester seat in last week’s by-election, will be sworn in as an MP tomorrow.

Sir Keir discusses his future with wife Victoria at Checkers in the Prime Minister’s countryside this weekend

Sir Keir is under pressure to clarify his intentions ahead of Tuesday’s Cabinet meeting. Another Labor leader said: ‘He was faced harshly with the fact that the support was not there.

‘The truth is that everyone knows this is no longer a tenable proposition. There’s sadness in everything, but sometimes in politics it’s inevitable.’

A Cabinet minister said Sir Keir was “going through the troubles calmly” after a series of meetings with his closest allies in recent days.

‘He just wants to do the right thing for his country and after talking to the people he wants, he’s now spending quality time with his most important advisor, Vic.’ Another ally said Lady Starmer now carries more weight than her close advisers and is now the only person she listens to.

The Starmer loyalist said until recently he was of the view that the Prime Minister should act decisively and challenge his critics. He said: ‘Vic was of the view that ‘you just have to keep going.’

Another insider made it clear that her influence on her husband is crucial. ‘It’s simple, she’s his rock,’ he said.

It was Lady Starmer who apparently stopped Sir Keir from throwing in the towel after some Cabinet colleagues told him the game was up, following Labour’s disastrous results in May’s local elections.

But as a No 10 source said: ‘Vic has been crucial in discussing things with Keir.’

This was despite Downing Street previously insisting Lady Starmer had no say in the machinery of government. She has kept a low profile in Downing Street, especially when, shortly after the 2024 general election, she came under fierce criticism (as did her husband) about party donors paying for her clothes.

The couple has also strongly defended their family’s privacy, especially when it comes to their son and daughter, who are now 18 and 15.

No 10 has previously insisted Lady Starmer, who works as an occupational therapist for the NHS, is not involved in the Government’s political affairs. But insiders suggest that this has understandably changed and he now plays a very political role.

This is the inevitable result of the ‘hollowing out’ of Sir Keir’s operation at Number 10, according to one source.

Lady Starmer is often at the Prime Minister’s side at major state events. Last week she flew with Sir Keir to the G7 world leaders summit in Evian, France.

Last night a Conservative Party source said: ‘The only person Sir Keir has left in his corner is his wife. If he had any sense he would have put him out of his misery and told him to get his act together.’