Keir Starmer will finally publish the long-overdue Defence Investment Plan today – including a £5billion drone 'transformation'.

But the outgoing Prime Minister drew scorn after it emerged only £1billion of this is fresh investment, with a £4billion drone programme having been announced last year.

Critics fear that whatever is in the plan, which is being released more than a year after it was promised, will be massaged figures and repackaged promises, rather than a blueprint to keep Britain safe in future warfare.

The bid to manufacture hundreds of thousands of drones over the next four years is a major part of the DIP.

That could rise to millions of drones at a time of conflict – Ukraine expends 200,000 every month to thwart Russian attacks.

The DIP will also include proposals to build six so-called 'budget warships' – replacing more expensive destroyers.

But the DIP has already cost Labour two high-profile resignations – John Healey as defence secretary and Al Carns as Armed Forces minister. 

They quit following the Prime Minister's failure to overrule the Treasury and his putting forward of a deal seen as tens of billions of pounds short.

Service chiefs say a cash injection of £28billion over four years is needed to make the UK secure – but the soon to depart PM has only offered, it is suggested, £14.5billion.

Tory defence spokesman James Cartlidge said: 'This is too little too late. Too little because it is barely more than John Healey and Al Carns resigned over, and too late because the plan is almost a year overdue. It is only being rushed through because Keir Starmer is desperate for a legacy.

'The plan is not worth the paper it is written on. The next prime minister needs to cut welfare and give our Armed Forces the funding they need.

'All Labour MPs want is more benefits. Labour are the welfare party. Britain deserves better than a failed Prime Minister forcing an inadequate defence plan on the nation.' Nato secretary general Mark Rutte has previously criticised members of the alliance for falling behind on military investment.

But at Downing Street yesterday he praised Sir Keir and added he was looking forward to working with Andy Burnham.

Mr Rutte, who has been criticised for flattering US President Donald Trump at every opportunity while failing to deliver on policy, thanked Sir Keir for 'everything' he has done for defence and 'everything you are doing to ramp up defence spending, to ramp up defence industrial production, I really want to thank you for all of that, it is really crucial'.

The DIP has been refocused since the Healey and Carns departures, with Defence Secretary Dan Jarvis ensuring troops receive the most modern equipment. Today's unveiling is expected to include the retiring of existing capabilities.

Mr Jarvis said last night that the character of warfare was 'rapidly changing' and that the conflicts in Ukraine and the Middle East were 'defining' how wars are fought.

In present and future conflicts manned ships, aircraft and vehicles will act as 'mother ships' for vast numbers of uncrewed platforms.

As if to emphasise the fast-moving changes in defence thinking, the vast £3.5billion HMS Queen Elizabeth aircraft carrier was a sorry sight in Portsmouth yesterday beneath a canopy of tents and scaffolding.

In an age of crewless warships and autonomous platforms the carrier is considered by some anachronistic, so too her sister ship, the HMS Prince of Wales. 

Together they cost Britain £7billion, a sum that depleted the Royal Navy's coffers resulting in precious few frigates and destroyers at sea and, most alarmingly, not a single 'hunter killer' submarine being available to defend the submarines carrying this country's nuclear deterrent.

The carriers have also proved alarmingly unreliable, with each suffering propeller problems that have cut short their itineraries.

Last night, Sir Keir said: 'This game-changing investment will strengthen our Armed Forces on land, air and sea, ensuring our servicemen and women have cutting-edge capabilities to deter evolving threats and keep British people safe.

'At the same time we're backing British innovation, industry and jobs and delivering opportunity to every corner of the country.'