Defence chief: UK not ready for the 'kind of full scale conflict we could face'

The UK is not ready to defend itself in the event of a full-scale European war.

Lots of people have said it. But now it has come from the professional head of the armed forces, the Chief of the Defence Staff (CDS).

“Since end cold war we have taken a peace dividend, and we are not as ready as we need to be for the kind of full scale conflict that we might face,” Air Chief Marshall Sir Richard Knighton told the parliamentary defence committee on Monday.

The MOD budget is always stretched, but that problem has come into much sharper focus as US President Donald Trump’s commitment to Nato has looked ever more shaky.

But how quickly can the UK change its state of readiness?

Knighton told MPs: “It is a statement of the obvious that we can’t do everything we would want to do, as quickly as we would want to do it, within the context of the budget we’ve set.

“And that requires ministers to make difficult trade-offs.”

Those trade-offs should have become more apparent in a Defence Investment Plan, which was due to be published before Christmas but which has yet to appear.

The Plan is intended to figure out how last year’s Strategic Defence Review will be paid for and what current capabilities may have to be dropped.

Added to that, there have been a series of newspaper reports suggesting that in December, Knighton told the prime minister that there was a £28bn black hole in the spending plans over four years.

The CDS confirmed on Monday there had indeed been a meeting in December, but the subject matter was classified as secret and he couldn’t talk about it.

But no one in Government has denied those reports.

Prime Minister Keir Starmer photographed with Sir Richard Knighton in May 2025. / Credit: PA

The longer term outlook is that the Government has committed to spending 3.5% of GDP on core defence.

Knighton told MPs that all of that money would be needed to meet the full demands of Nato.

What everyone in the room knew, is that the government has only committed to spending that much by 2035, at the next of the next Parliament. As yet there is no plan for finding that cash.

So what happens if there’s a full scale war in Europe before then?

Well in a way there already is, in Ukraine. And the CDS said that so long as Russia is ‘fixed’ there it couldn’t launch a full scale attack elsewhere.

The question is how quickly Russia can rebuild its forces if and when the Ukraine war finishes?

No one knows for sure, but Knighton believes the UK, and Nato, have to rearm quickly enough to deter Putin from having another go somewhere else.

And at the moment, we are not ready.