Angela Rayner called Scottish Labour leader before he publicly called for Keir Starmer to resign

A source close to Ms Rayner confirmed a conversation between the two had taken place but insisted it was a "courtesy" call, adding Sir Keir still had her full support, reports The Telegraph.

The Prime Minister insisted his top team was "strong and united" as he thanked ministers at a Cabinet meeting for rallying around him with public messages of support.

Sir Keir also said his Government should be "acting together" over the release of files on Peter Mandelson after Wes Streeting published his exchanges with the former ambassador.

He expressed his "100 per cent" support for Mr Sarwar, who had cited concern that the "distraction" from Downing Street would harm his party’s chances of unseating the SNP in May’s Holyrood elections.

In Wales, Labour First Minister Eluned Morgan insisted Sir Keir had her "full confidence."

Meanwhile, Greater Manchester Mayor Andy Burnham reaffirmed his support but said he had spoken to Sir Keir about the party needing a "strong sense of a stronger team again."

Downing Street is increasingly confident Mr Sarwar’s call for the PM to go was not part of a coordinated plot.

The Scottish Labour leader is also understood to have spoken with Wes Streeting ahead of his bombshell press conference.

Mr Sarwar is now braced for a fallout with Downing Street just three months shy of the Scottish Parliament election.

He posted a campaign video on his social media channels on Tuesday insisting he is putting country before party.

But his party faces an almighty challenge convincing the Scottish public to back them with a recent YouGov poll suggesting Reform UK has overtaken them in terms of voting intention.

The SNP remains at the front of the pack, holding a 14 point advantage over Nigel Farage’s insurgent party.

Labour linger behind with 15 per cent of the constituency vote, a hefty drop from the SNP’s 34 per cent total and Reform UK’s 20 per cent.

The Conservatives, meanwhile, sit behind them with 10 per cent of the vote, tie with the Liberal Democrats, while the Green Party sit on nine per cent.

For the poll, 1,113 Scottish adults were asked for their opinion ahead of the vital election.