The UK is fully equipped to fight a war against Russia should Nato be attacked, a senior military officer has said.

Air Marshal Richard Knighton, deputy chief of the defence staff, rejected claims made by one of his predecessors, General Sir Richard Barrons, that “Nato isn’t ready”.

General Barrons told the House of Commons Defence Committee on April 19 that Nato “will have a call to make” should Russia attack members of the alliance, adding: “And that call would be easier if we had made any preparations at all to act in those circumstances at the speed required, and we have not.”

But AM Knighton told the same committee on Tuesday that Nato’s mission was “to deter an attack” and that Russia “is learning a lesson about the cost of invasion” in Ukraine.

Asked directly by Conservative MP Richard Drax whether the UK had enough equipment and ammunition to fight Russia for more than a week, AM Knighton replied: “Yes.”

He said: “General Barrons is a renowned commentator on such matters since he retired.

“The scenarios that we work through are many and varied, but if you are asking does Nato have the ability to blunt a Russian attack, yes it does.”

BrexitTobias Ellwood, the Conservative chairman of the Commons Defence Committee, described the conflict in Ukraine as ‘ever increasingly a proxy war’ (Yui Mok/PA)

However, he said he was unable to comment on claims by a retired US general that a joint exercise with the US Army in 2021 saw UK forces run out of ammunition in a week during a simulation of a Russian invasion.

AM Knighton did confirm that some equipment stockpiles were being increased following Russia’s invasion of Ukraine, but others had been depleted by the decision to send arms to Kyiv.

The committee received a less direct answer to chairman Tobias Ellwood’s question regarding what success in Ukraine looked like.

Mr Ellwood had asked the same question of Defence Secretary Ben Wallace in the House of Commons on Monday. Mr Wallace said Putin “must fail” but what that meant was “as much a matter of Ukraine’s choice as it is of anybody else”.

Ministry of Defence Permanent Secretary David Williams gave a similar answer on Tuesday, who said it was “a fluid question”.

Mr Ellwood said: “I do encourage the MoD, through Nato, the Defence Secretary, to establish and confirm what mission success looks like, because that then determines what equipment you pile in.

“This is ever-increasingly a proxy war which will spill beyond Ukraine if any part of Ukraine remains in Russian hands and these are the difficult questions that need answering, potentially by Madrid at the Nato summit.”