The head of the UK Armed Forces said Britain is not sufficiently prepared for the possibility of a full-scale conflict.
Chief of the Defence Staff Sir Richard Knighton told MPs the country is “not as ready as we need to be for the kind of full-scale conflict we might face.
His comments came amid reports that the Ministry of Defence faces a £28bn funding shortfall over the next four years.
Sir Richard said the long-delayed defence investment plan is still being worked on but could not give a publication date.
Pressure has mounted on the UK to raise defence spending following Russia’s invasion of Ukraine and the re-election of US President Donald Trump.
The government has pledged to raise defence spending to 2.5% of national income by 2027 and to 3.5% by 2035.
Sir Richard said budget constraints mean ministers must make difficult trade-offs on defence priorities.
He confirmed discussions with Prime Minister Sir Keir Starmer on defence planning but said the details were classified.
Sir Richard said the UK could meet commitments to send troops abroad in the short term but broader readiness remains a concern.
He warned the UK lacks a comprehensive plan to mobilise the NHS in the event of a major European war.