The head of the Navy has warned the Libyan conflict can only be sustained if the Government makes defence cuts elsewhere.

First Sea Lord Admiral Sir Mark Stanhope said ministers would have to "reprioritise" - making cuts in firepower elsewhere - if the Nato-led campaign lasts beyond the UK's existing six-month commitment.

He indicated that may involve diverting warships patrolling "home waters" around the British Isles to the Mediterranean, closer to the conflict.

In comments that are likely to fuel further debate over cuts to the defence budget, Sir Mark said he was confident parts of the operation would have been faster and cheaper if the aircraft carrier HMS Ark Royal had not been scrapped.

But the Navy chief refused to directly criticise the decision to axe the vessel and its Harrier jump jets taken as part of the Strategic Defence and Security Review (SDSR) .

"How long can we go on as we are in Libya?" he asked at a media briefing.

"Certainly in terms of Nato 's current time limit that has been extended to 90 days, we are comfortable with that.





"Beyond that, we might have to request the Government to make some challenging decisions about priorities.

"If we do it longer than six months we will have to reprioritise forces. That is being addressed now.

"It could be from around home waters. I will not prejudge what that decision will be."

He pointed out Harrier jets could have been deployed in 20 minutes rather than the 90 minutes taken to send Tornado and Typhoon aircraft from the Italian air base at Gioia del Colle.

Ministers have previously argued that Britain could do without the HMS Ark Royal or Harriers because such bases can be used.

"We have to look forward and go for what is in the pipeline, which I have already indicated is challenging enough," Sir Mark said.

"There is far too much about what could have been as opposed to what is."





British forces have been in action in Libya since March. Two weeks ago, Nato extended the mission by another 90 days and taxpayers are now expected to foot a £1bn bill.

In March, Chancellor George Osborne said UK involvement would cost tens of millions of pounds. By the end of April, the cost had soared to £300m and was increasing by as much as £38m a week.

Sky's defence correspondent Niall Paterson said part of the challenge has been the changing nature of the conflict and the resilience of Colonel Gaddafi - meaning the operation has become more drawn-out and costly than first expected.

He said: "There is no immediate end in sight and some members of the coalition are already scaling down their involvement."

Air Vice Marshal Tony Mason, the RAF's former Air Secretary, said it was an "exaggeration" to suggest the conflict was putting British defences at risk.





"I could understand Admiral Stanhope's concern because of course the Navy has been drastically cut and is facing more cuts," he told Sky News.

"But one of the reasons why the response has been so measured... is to ensure that pressure can be kept, albeit at a lower level than some would like, for an extended period."

He added: "The fundamental problem... is I genuinely believe the alliance underestimated the reaction they were going to get from Gaddafi.

"Britain's defence is not weakened, but a fundamental weakness of the defence review has clearly been shown."

Defence Secretary Liam Fox insisted the UK's leading role in the the Libya conflict showed it had adequate resources.

Dr Fox said: "We continue to have the resources necessary to carry out the operations we are undertaking and have spare capacity with the Royal Navy Cougar Taskforce which is currently on exercise in the Gulf."

Jim Murphy MP , Labour's shadow defence secretary, said he hoped the warning prompted a response from the Government.

"This is yet another convincing argument in favour of reopening the defence review, which has not survived its first contact with world events," he said.

In recent weeks the head of the Army has warned defence spending will need to rise if Britain is to remain capable of fighting a war.

Chief of the General Staff General Sir Peter Wall said Government cuts would need to be reversed if ministers wanted to send UK troops into battle just nine years in the future.



