Rachel Reeves has sounded alarm about the danger of a Labour lurch to the Left as the party faces civil war.

The Chancellor delivered a stark message that the Government must not 'deviate' from her fiscal rules.

With Andy Burnham poised for a leadership challenge if he wins the Makerfield by-election today, Ms Reeves also appeared to line up firmly behind Keir Starmer.

She insisted that Sir Keir is 'our PM' and she was intending to 'continue' as his Chancellor.

The comments - at the Times CEO Summit in London - come after rumours Ms Reeves had been wooing Mr Burnham to keep her in No11 if he takes over the top job.

However, allies of the Greater Manchester Mayor regard the idea as highly unlikely given she is about as unpopular as the current premier. Ed Miliband has been widely tipped for the key job instead.

The markets have been spooked by signs that Mr Burnham could take Labour to the Left with a major spending splurge funded by borrowing and even more tax.

He has hinted at wealth taxes, revaluing council tax and called for nationalisations.

But Mr Burnham has also executed screeching U-turns on a slew of ideas, including ruling out billions of pounds of compensation for so-called WASPI women just hours after supporting the prospect. 

The former Cabinet minister caused a furore at last year's Labour conference in Liverpool after suggesting in an interview that politicians had to 'get beyond this thing of being in hock to the bond markets'.

But he later seemed to row back from these comments, saying last month he supported Ms Reeves's fiscal rules.

He told ITV: 'There needs to be a plan to get debt down, but beyond that, we need to change politics and take the turbulence out of British politics, because that is a cause of uncertainty that then has that impact in the markets.'

Ms Reeves said today: 'We got elected on the promise to return stability to the economy, and anyone who wanted to deviate from that will not be fulfilling the manifesto commitments.'

She was speaking as voters headed to polling stations across Makerfield in a contest that could see Greater Manchester Mayor Andy Burnham return to Westminster and challenge Sir Keir Starmer for the leadership of the Labour Party.

Asked what advice she would give to a potential successor, Ms Reeves said there was 'no vacancy' for her job.

She said: 'Keir is our Prime Minister, I am his Chancellor.

'I am getting on with the job of being Chancellor of the Exchequer and I plan to continue in that role.'

Sir Keir has vowed to fight on, explicitly saying that he will be a candidate if there is a leadership contest. 

But in a worrying sign for the PM, even allies appear to be hedging their bets. A host of big beasts have been in Makerfield to help out with the last day of the campaign. 

Alongside Angela Rayner and deputy leader Lucy Powell, supposedly loyalist Cabinet minister Darren Jones was spotted. 

However, neither Ms Reeves nor Sir Keir himself have been to the constituency. The PM is understood to be working in Downing Street today.