The RAF is planning on the basis that operations over Libya will last at least six months, its chief has said.
Air Chief Marshal Sir Stephen Dalton warned the service would need “genuine increases” in its budget to run the range of operations ministers demand.
He told the Guardian that without more investment, the RAF would struggle to maintain levels of capabilities.
The Army and Royal Navy will set out details later of the first wave of job losses from October’s defence review.
Ministers have denied the review is simply a “cost-saving exercise”.
Sir Stephen said his assumption was that the RAF’s warplanes and surveillance aircraft would be needed over Libya for a number of months, rather than weeks.
The key factor is that if we are to meet the requirements laid upon us, there is no question that more investment will be needed to achieve that”
End Quote Sir Stephen Dalton Air Chief Marshal
“In general terms [we] are now planning on the basis of at least six months, and we’ll see where we go from there,” he said.
A poll for BBC News on Sunday suggested that two-thirds of people believed Britain’s military involvement in Libya would go on for some time.
Of 2,000 people asked, 65% said the UK’s involvement in Libya “will last for some time”, while just 14% chose the option “will be over pretty quickly”, and 20% did not know.
Foreign Secretary William Hague said on Sunday that the military intervention in Libya would not lead to a stalemate between pro-Gaddafi forces and rebels.
He said Col Muammar Gaddafi’s regime had no future because it was isolated and could not sell any oil.
Meanwhile, Scottish police and prosecutors are due to meet Foreign Office officials on Monday to try to gain access to former Libyan foreign minister, Moussa Koussa, who arrived in the UK last week.
They want to talk to Mr Koussa about the 1988 Lockerbie bombing in which 270 people died.
Sir Stephen issued a warning that the RAF would need an increase in spending from the next Comprehensive Spending Review in 2014.
Without “genuine increases”, he said the RAF would find it “very difficult” to maintain its current levels of capability – with operations in Afghanistan, the Falklands and Libya.
- 5,000 RAF personnel axed over five years
- 5,000 Navy personnel cut
- 7,000 army personnel cut
- 25,000 civilian MoD staff axed
“The key factor is that if we are to meet the requirements laid upon us, there is no question that more investment will be needed to achieve that,” he said.
“What I am seeking to do is maintain core competencies and bricks on which we can then build the future.”
Commenting on Sir Stephen’s Guardian interview, shadow defence secretary Jim Murphy said forces’ families would want to know that those “serving on crucial operations in Libya will not be sacked on their return”.
“On the day the air chief marshal warns about the pressures being placed on the RAF, and when our forces are being asked to do more overseas, the country will want the Tory-led government to explain the impact of their actions,” he said.
“Our forces deserve better. The government should pause, think again and reopen their rushed defence review.”
The financial difficulties being faced by all three armed services will be underlined when the Army and Royal Navy set out their redundancy programmes later.
Soldiers and sailors in the groups targeted for job losses will be seen by their commanding officers on Tuesday.
It is expected that just under 600 personnel in the Army and 1,600 from the Royal Navy will be made redundant in September. The RAF spelled out its plans for 2,700 lay-offs last month – 1,020 of whom will go by September.
In total, the RAF and navy will lose 5,000 jobs each, the Army 7,000 and the Ministry of Defence 25,000 civilian staff.
Unveiling the strategic defence and security review in October, Prime Minister David Cameron said defence spending would fall by 8% over four years.
He said the UK would still meet Nato’s target of spending 2% of GDP on defence and would continue to have the fourth largest military in the world and “punch above its weight in the world”.
But he said the country had to be “more thoughtful, more strategic and more co-ordinated in the way we advance our interests and protect our national security”.
In February, the Army apologised to 38 soldiers who learned they were losing their jobs by e-mail.
The men – all long-serving warrant officers and including one working in Afghanistan – were told they were victims of the defence cuts.