UK military chiefs have been asked to find £3.5bn in "efficiencies" and other savings this year, even as Sir Keir Starmer says he is readying his armed forces for war, sources have signalled.
One source said the heads of the army, Royal Navy, Royal Air Force and other top brass were due to meet this week to discuss the funding pressures.
A second source said the squeeze is because the current budget is insufficient simply to deliver the programme of record - let alone ambitions set out in a major review of defence that was published last June to rebuild and rearm in response to escalating threats.
A third source said that the Ministry of Defence - like all government departments - has to operate within the agreed budget set out by the Treasury.
Defence officials had been holding out for the possibility of more money being made available faster as part of a major, 10-year plan to invest in new equipment and capabilities.
However, the government has still not signed off on the Defence Investment Plan (DIP) - even though it should have been published last autumn.
It means that there is no let-up in the financial squeeze, leading to further demands on military officers and civil servants to look for new ways to cut costs.
The revelations about the in-year cash crisis emerged as Lord George Robertson, the lead author of the prime minister's Strategic Defence Review and a former Labour defence secretary, prepares to issue a devastating critique of the government's record on defence.
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In a speech this evening, he will accuse the prime minister and his chancellor of "corrosive complacency" that has left the armed forces "underprepared" for the threats they face.
Lord Robertson, also a former head of the NATO alliance, will take particular aim at Rachel Reeves, her apparent lack of interest in defence and the incompatibility of vast welfare spending with supercharging the defence budget.
He will accuse "non-military experts in the Treasury" of "vandalism", adding: "We cannot defend Britain with an ever-expanding welfare budget."
Asked about the claim that military chiefs have been urged to find £3.5bn in efficiencies and other savings in-year, a Ministry of Defence spokesperson said: "The defence budget is rising to record levels as this government delivers the biggest boost to defence spending since the Cold War, totalling £270bn this parliament alone.
"Demands on defence are rising, with growing Russian aggression, the crisis in the Middle East and increasing operational requirements.
"We are finalising our Defence Investment Plan that we will publish as soon as possible, putting the best kit and technology into the hands of our forces, rebuilding British industry to make defence an engine for growth and doubling down on our own commitment to NATO."
A request to make efficiency savings is different to a budget cut. Military chiefs have repeatedly been requested over the years to find ways to do things cheaper or more efficiently.
They will typically draw up lists of options - including extremely unpalatable ones that could not be accepted - in a back and forth with defence and Treasury officials to try to make the in-year finances work.
In a defence review in 2015, however, much of the investment plans to buy more military kit were predicated on billions of pounds in unspecified efficiency savings that were never achieved, leaving the armed forces more hollow.
(c) Sky News 2026: UK military chiefs asked to find £3.5bn in savings - and get ready for war

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