The business and trade secretary, Peter Kyle, told Sky News that he has not spoken to Starmer since Friday - but he had a “very detailed conversation” with him then, which he said was “private” and “personal”.

“The prime minister was calm. He was thoughtful. He led the conversation,” Kyle told Trevor Philips.

“Repeatedly, the prime minister asked about the country. Not once in that conversation, which was a lengthy conversation, did he ever ask about self-interest; it was always about the country. And I think that is the tone of the conversation I had with him.

“It was frank, and I think that is the mindset that the prime minister is in as he goes into this weekend, through which he has been working very hard as prime minister, as he always does, but also trying to make time to reflect on the political challenges at the moment.”

Kyle went on to say that Starmer is “making time to reflect on the political realities, challenges and opportunities that he finds himself in”. Over the weekend, the prime minister has been at his country retreat, Chequers, spending time with his wife, Victoria.

Good morning and welcome to our live coverage of UK politics. The British prime minister, Keir Starmer, is expected to resign on Monday and is preparing to set out a timetable for an orderly departure from No 10, according to the Observer.

The paper reports that Starmer, who has insisted he would fight any leadership challenge, now recognises his position is untenable after talking with cabinet ministers, party donors and trade union leaders over the last couple of days.

“He’s come up hard against the reality that the support isn’t there,” one source told the Observer. “The truth is everyone knows this is no longer a tenable proposition. There’s a sadness about it all, of course, but sometimes there’s just an inevitability in politics and as Boris Johnson said, ‘When the herd moves it moves’.”

No 10 has denied the report that Starmer is about to resign and said he is getting on with the job of prime minister.

The number of MPs backing Andy Burnham for the Labour leadership surged following his triumphant byelection victory in Mankerfield last week which showed he could fight off Reform in a general election.

The Greater Manchester mayor is expected to be in Westminster on Monday to be sworn into the House of Commons. He is reportedly planning to speak to Starmer afterwards and present him with a list of backers – which he is said to be seeking to get up to 200 – in an attempt to press him to step down and set out a transition.

Allies of Burnham favour a longer wait to allow them to prepare for government, which could mean Starmer could remain prime minister for months.

The number of Labour MPs publicly calling for Starmer to go has exceeded 100 – just under a quarter of the party’s MPs – and includes many who want a transition of power without the spectacle of a potentially messy leadership contest.

Starmer is under pressure to reveal his plans before a crunch cabinet meeting on Tuesday, where a number of ministers are expected to tell him his time is up.