Prime Minister David Cameron has called the UK a “first-class player” in defence, after former US Defence Secretary Robert Gates said military cuts had left the UK diminished on the world stage.
A reduction in staff in the Armed Forces would mean the UK would no longer have the “ability” to be a full military partner to the United States, Mr Gates said on Thursday.
Mr Gates told BBC Radio 4’s Today programme that planned Government cuts to the Armed Forces would limit the UK’s global position.
The Prime Minister insisted that the UK's defence budget remained the fourth largest globally and more investment was being made to enhance its future capabilities.
During a visit to the Crossrail project in central London, Mr Cameron said: "I don't agree with him. I think he has got it wrong.
"We have the fourth largest defence budget anywhere in the world. We are investing in future capabilities.
"We are a first-class player in terms of defence and as long as I am Prime Minster that is the way it will stay," Mr Cameron said.
The Army is to be cut from 102,000 to 82,000 personnel by 2020. The number of staff in the Royal Navy will fall by 6,000, while the RAF will lose 5,000 service personnel.
Mr Gates, who served under Presidents Barack Obama and George W Bush, told the news programme that naval cuts in particular would be the most damaging.
He added that for the first time since the First World War Britain does not have an operational aircraft carrier.
In reference to UK’s ability to fight on land, sea or air, he said: "With the fairly substantial reductions in defence spending in Great Britain, what we're finding is that it won't have full spectrum capabilities and the ability to be a full partner as they have been in the past."
His concerns come after the Chief of the Defence Staff, General Sir Nicholas Houghton, said that military manpower was increasingly seen as an “overhead” and that Britain was in danger of being left with hollowed out armed forces. He added that the UK’s “exquisite” equipment would be left without soldiers, sailors, and airmen to use it.
He told the Royal United Services Institute military think-tank that the Royal Navy was "perilously close" to its "critical mass" in terms of manpower.
In 2011, Prime Minister David Cameron stressed that the UK retained a “pretty full spectrum capability” after the three service chiefs warned its reach would be lessened.