Britain could struggle to mount another military operation on the scale of the intervention in Libya, MPs warned today.
The Commons Defence Committee said the government would face "significantly greater challenges" if it had to conduct a similar size mission in future.
The committee concluded the international military intervention in Libya - which led to the overthrow of Muammar Gaddafi - had been justified, given "the gravity of the situation and potential consequences of inaction" for the civilian population.
However it said the mission - codenamed Operation Ellamy - was carried out before key defence cuts in the government's Strategic Defence and Security Review (SDSR) had been implemented.
It said the RAF had been forced to extend the life of its ageing Nimrod R1 spy planes for the operation while the Royal Navy had had to drop important tasks - such as counter-drugs operations - because of its Libya commitments.
"We believe the Government will face significantly greater challenges should an operation of similar size be necessary in the future and it will need to be prepared for some difficult decisions on prioritisation," the committee said.
"We consider that Operation Ellamy raises important questions as to the extent of the United Kingdom's national contingent capability. We urge the Government to review the United Kingdom's capacity to respond to concurrent threats.
"This work should be conducted as a matter of urgency before the next Strategic Defence and Security Review."
The committee said there were "contrary opinions" over the legality of the Libya mission and concerns had been expressed that the true goal was "regime change", even though it was not authorised by United Nations Security Council resolutions.
"Although it is difficult to see how the mission could have been successfully completed without Col Gaddafi losing power, we are concerned that this, rather than the protection of civilians as set out in the resolution, came to be seen by some countries as an integral part of the mission," it said.
"The apparent conflict between the military and political objectives meant that the Government failed to ensure that its communication strategy was effective in setting out the aims of the operation."
The committee acknowledged there were fears the intervention in Libya had made it impossible for the international community to take decisive action over other countries - pointing to Russian and Chinese concerns over Syria.
However it rejected the suggestion that Britain should not have supported military action in Libya.
"It is impossible for us to tell what the consequences would have been of allowing the killing of civilians in Benghazi, but we consider that the determination of the Arab League and of most countries of the United Nations that a massacre would be unacceptable was an example of the international community acting as it should," it said.
The committee chairman James Arbuthnot said the mission in Libya had been successful in discharging the UN mandate.
"The real test is whether the success of this mission was a one-off or whether the lessons it has highlighted mean that future such missions can be successfully undertaken, whilst maintaining the UK's capability to protect its interests elsewhere," he said.
Defence Secretary Philip Hammond said the operation had shown the UK still had the ability to project military power around the world.
"The Libyan campaign shows that we retain the contingent capability to conduct operations in addition to our commitments in Afghanistan, counter-piracy off the Horn of Africa, Gulf security and standing tasks such as the Falklands and defence of the UK," he said .
"Conducted against the backdrop of a multibillion-pound black hole in the defence budget, the SDSR required tough decisions whose underpinning logic the committee has previously agreed with.
"We retain the capability to project power abroad and meet our Nato obligations, supported by what is the world's fourth largest defence budget."