Allies of Keir Starmer have warned that he could be replaced by ‘Labour’s Liz Truss’ if he is ousted in a chaotic leadership contest.

Labour MPs have been warned that booting out the Prime Minister in the wake of next week’s local elections could usher in a disastrous Left-winger like Ed Miliband or Angela Rayner.

Allies of the PM claim a lurch to the Left could undermine market confidence in the Government and send borrowing rates spiralling, crashing the economy.

One source told the Daily Mail: ‘If you just flip the coin because you are angry, you could end up with chaos – it would be a totally irresponsible thing for a governing party to do.

‘You could end up with Ed Miliband or Rayner and that would be the end for us. A Left-wing Liz Truss, with no real mandate, would be the end of the Labour Party.’

Labour MPs are weighing up whether to ditch Sir Keir after months of dire poll ratings.

Elections expert Robert Hayward warned this week that the party is on course to lose three-quarters of the seats it is defending in Thursday’s local elections, with as many as 1,850 councillors losing their jobs.

Labour, which has governed in Wales since devolution, looks set to come third in the principality. The party is also struggling to avoid third place in Scotland, where it once had hopes of finally dislodging the SNP.

But MPs critical of Sir Keir are divided on who should succeed him – raising the prospect of a chaotic and unpredictable leadership contest.

In a highly unusual intervention, former Conservative Prime Minister Sir John Major warned Labour against ditching Sir Keir in favour of what would be the seventh prime minister in a decade.

He told the BBC that people had to stop treating politics as a ‘game show’. He urged political parties to focus on developing solutions to long-term problems, like Britain’s ageing society, instead of obsessing about individual leaders.

‘The fate of individual politicians doesn't really matter as much as the development of the right policy,’ he said. ‘I mean, it isn't a good idea to keep changing prime ministers.’

The Mail on Sunday revealed last week that Ms Rayner has been phoning senior members of the parliamentary Labour party to urge them ‘it’s now or never’ if they wish to remove the PM.

The former Deputy Prime Minister is currently favourite to succeed Sir Keir if a contest is triggered quickly before Greater Manchester Mayor Andy Burnham can seek another Commons seat.

However, dozens of Labour MPs are opposed to her taking charge. And she remains under investigation by HM Revenue and Customs over her failure to pay £40,000 in stamp duty on a luxury apartment in Hove, which forced her resignation from the Cabinet last September.

Some critics have now launched an ‘anyone but Ange’ campaign designed to keep her out of No 10.

One Labour MP told the Times: ‘There’s a big will behind the “anyone but Ange” sentiment. If we do nothing, we are sleepwalking into an Angela Rayner premiership.’

If Ms Rayner were to fall by the wayside, the next favourite to succeed Sir Keir would be Mr Miliband, who could find himself handed the keys to No 10 a decade after he was roundly rejected by the public at the 2015.

One MP told the Daily Mail: ‘Miliband is tried, tested and failed as a leader. Set aside his ideas, which would give us real problems with the markets, it would be impossible to explain to my constituents why we were installing someone they had already said no to.’

Health secretary Wes Streeting is said to be considering a bid for the leadership, but polls suggest he would struggle to beat a Left-winger in a final run-off with Labour Party members. 

The standoff increases the chances that Sir Keir could survive in the short term while supporters of Andy Burnham plot his return to Westminster.