A Labour civil war broke out on Tuesday night after Keir Starmer moved to force through military spending blueprints – including cuts in defence capability – before Andy Burnham takes over in No 10.

Sir Keir's charge to deliver his ten-year Defence Investment Plan (DIP) enraged allies of the PM-in-waiting and drew criticism from a former Civil Service chief.

The outgoing Prime Minister wants to present the DIP ahead of a Nato summit next month – despite fury over its failure to meet the needs of our armed forces.

Military chiefs have warned Sir Keir's planned £10billion increase in defence spending over four years falls so short of requirements that operations considered critical to national security will have to be 'dialled back'.

Sources close to Mr Burnham declined to comment in detail on his views on defence spending but it is understood he wants to examine the plans and 'make the decision himself'.

He is thought to have discussed the issue privately with both John Healey – who quit as defence secretary over the plan's lack of funding earlier this month – and the Foreign Secretary Yvette Cooper, who is among those tipped as a potential successor to Chancellor Rachel Reeves.

An ally of Mr Healey said: 'We know this DIP settlement falls well short and an incoming PM will still have to meet the same requirements. So clearly there is a strong argument against publishing a half-baked DIP now.'

Former Cabinet Secretary Lord Case claimed the outgoing PM would be 'wasting his breath' should he bring forward proposals that were later scrapped by his successor.

And Kevan Jones, chairman of parliament's intelligence and security committee, told the Daily Mail it made no sense for Sir Keir to sign off such a critical decision just days before leaving office.

The former Labour defence minister said: 'If it is published as it is, it is going to remain at the top of the in-tray of any new prime minister because the question of national security cannot be ignored. 

'There is no point putting out a plan now to spare the PM's blushes at the Nato summit if it is going to have to be revisited immediately by his successor.'

On Tuesday night Dan Jarvis, appointed Defence Secretary by Sir Keir following Mr Healey's resignation, confirmed the DIP will be published before the Nato meeting in Ankara on July 7.

In a keynote speech at the RUSI Land Warfare Conference in London, Mr Jarvis revealed the DIP will 'lay out significant savings'.

He said he had spent the 12 days of his tenure as defence secretary 'scrutinising every line of spend to make every pound count'.

The DIP could now be published in the coming days, after Mr Jarvis said the need to do so was 'urgent'.

And Conservative leader Kemi Badenoch reminded the Government on Tuesday that the UK is pouring 'one pound in three' into benefits and only 'one in seven' into the armed forces.