The military needs more money for munitions and anti-missile systems, a senior officer warned as Rishi Sunak refused to say when defence spending would meet his target.
The Government is committed to increase defence spending to 2.5% of gross domestic product, a measure of the size of the economy, but the Prime Minister has declined to say when he would meet that aspiration.
Defence Secretary Grant Shapps told MPs he had lobbied Mr Sunak and Chancellor Jeremy Hunt for more cash in the Budget, but failed to secure an increase.
And deputy chief of the defence staff Lieutenant General Sir Rob Magowan said he would have to manage the “operational risk” that came with not having the resources he would like.
Appearing before MPs at the Commons Defence Committee, the senior Royal Marines officer said: “We’ve been very clear that the money the amount of money we’re spending on munitions at the moment … which is significant, does not meet, in all areas, the threats that we face.
“We’ve been clear that we need to spend more money, above the programme of record, on what we call integrated air missile defence.”
He added: “We have made it clear, if we were given additional money, what we would spend money on but we work within the money we’ve got and we carry the operational risk accordingly.”
But he insisted the UK was “ready for war” although he acknowledged it was not prepared for an enduring war against Russia.
Tory defence committee member Mark Francois said: “We couldn’t fight (Vladimir) Putin for more than a couple of months in a full-on shooting war because we don’t have the ammunition and the reserves of equipment to do it, that’s true isn’t it?”
The deputy chief of defence staff acknowledged that was true, although Mr Shapps pointed out that any such conflict would be fought alongside Nato allies who could collectively outgun Russia, rather than by the UK alone.
Mr Shapps said: “For people watching, and hearing that the UK isn’t ready for war exclusively with Russia, it’s important to understand that because we are in Nato and (mutual defence agreement) Article 5 exists, we would never be in that situation.”
Defence spending is expected to be around 2.3% of GDP next year, but will only reach 2.5% “when the conditions allow”, Mr Sunak told the Liaison Committee.
At the Defence Committee, Mr Shapps said “of course I made representations” for more money in March’s Budget, adding: “What kind of Secretary of State wouldn’t?”
He told MPs: “We are committed to going to 2.5%. Of course, as Secretary State for Defence, I argued that we should do that as possible.”