The UK’s “decimated” armed forces are increasingly causing concern within NATO, the Express understands. It has been claimed Britain’s credibility within the alliance is being “stretched wafer thin” by failing to meet NATO obligations amid glacial rearmament and delayed investment plans.

It follows outrage over the UK’s readiness to respond to a drone attack on an RAF base in Cyprus, with Type 45 destroyer HMS Dragon unlikely to arrive in the Eastern Mediterranean until next week. New Ministry of Defence (MoD) forecasts also show defence expenditure in 2027-28 is set to fall as a share of GDP, in stark contrast to the ramped-up spending of other Nato allies. A source told the Express that within the alliance, there is a “dawning realisation the UK is talking a good game but not walking the walk”.

They pointed out that while other allies are greatly accelerating defence spending in the face of continued Russian aggression, significant Labour plans to boost defence are not expected until the next Parliament.

The insider said they believe NATO officials think UK defence has “never been this bad” and risks “undermining faith in the alliance”. Another source said “goodwill to the UK is being eroded now”, warning that this will only increase as more NATO nations step up.

Liberal Democrat MP Mike Martin, a Defence Select Committee member and former Army officer, said some of these warnings tally with what allies have told him.

“They all had a similar message: the British armed forces have been stripped bare. The last week has really exposed that,” he said. He added: “Hollowed out is too polite [to describe the state of the military]. Decimated, gutted, ineffective, on its knees, unable to fulfil the tasks that we need it to and that we’ve agreed with NATO.”

Veteran and Conservative MP Ben Obese-Jecty accused Labour of failing to back up its rhetoric on defence with actions.

He said: “I think this is indeed an extremely worrying time. We look at our allies across Europe who are rearming at a tremendous pace. You’ve only got to look at the likes of Poland and the Baltics as to how seriously they’re taking defence, and look at the amount of extra funding Germany has provided to upgrade its armed forces.

“At the same time, our own armed forces are struggling to even get a Type 45 destroyer out to protect Cyprus in a current conflict.”

Shadow Defence Secretary James Cartlidge said: “Lots of people are rightly saying that our armed forces need a substantial rise in their budget, but few are saying exactly where the money should come from. In contrast, in December, I confirmed our plan for a Sovereign Defence Fund, to rapidly deliver drone tech to the Army, Royal Navy and RAF, paid for by transferring billions from Ed Miliband’s vanity net zero schemes to Defence.

“And we’ve now confirmed our plan to deliver 20,000 extra soldiers, fully funded by restoring the 2-child benefit cap. Starmer is paralysed on defence decisions because he’s blown the budget on welfare. In contrast, Kemi has the guts to take the tough decisions so we can actually stand strong in the world.”

It comes as the Defence Investment Plan (DIP), expected to be published last autumn, has been repeatedly postponed amid reports of a £28billion hole in the budget over the next four years. The plan is supposed to set how the Government will fund its Strategic Defence Review and is also expected to provide further detail of the capabilities and numbers intended for the military over the next decade.

The Express previously revealed the delay has “paralysed” Britain’s defence industry as concerns the DIP will be bad news for the military mount. One source said: “The Government and MoD have got no balls, nobody wants to make tough decisions.”

The military has drastically shrunk in size over the decades due to repeated funding cuts by successive governments, with the Army at its smallest manpower-wise since the Napoleonic era. A second insider said while the UK remains “very well regarded” within Nato for its leadership and experience, allies “don’t see us having the mass to make much of a difference anymore”.

They said Britain has some “first-class” kit, but there’s not enough to back it up, pointing towards the Navy’s six Type 45 destroyers — half of which are often out of action while undergoing maintenance — as an example.

The source added the UK finds itself “walking a tightrope” between an unpredictable US administration and being locked out of the EU’s defence fund, adding: “Stepping up in Nato is an open goal.”

They said Britain’s spending on conventional forces — recent reports suggest it is 1.75% of GDP — is “ridiculously small for a country of our size and ambitions” and said moving the Trident nuclear deterrent out of the MoD Budget should be considered.

Poland, which is set to spend 5% of its national income on defence by the end of this year, was identified as one nation which could overtake the UK in Nato.

Labour is under growing pressure to increase the defence budget, with the Conservatives calling for spending to reach 3% this Parliament rather than next. A new MoD forecast expects “core” defence spending to be some 2.13% of GDP in 2027-28 — a decrease from 2.2% projected in September.

However, this is not because of amendments to the defence budget, but instead because of fluctuations in estimates of the UK economy’s size for the period.

A government spokesperson said: “The UK is the third-highest defence spender of all Nato nations, and we are a leader in the alliance – from committing our nuclear deterrent to Nato to recently doubling the number of personnel to be deployed for Arctic and High North security.

“We are delivering the largest sustained increase in defence spending since the end of the Cold War, hitting 2.6% of GDP from 2027, and the UK defence budget will total £270billion across this Parliament alone. The UK has also made the historic pledge to hit 5% of GDP spend on defence and national security, with a target date of 2035.”