The armed forces is facing a further wave of cuts in the next financial year as the Ministry of Defence seeks to make more savings.
A three-month study, reporting in July, will consider how more personnel and equipment programmes could be axed.
It follows October's controversial Strategic Defence and Security Review (SDSR) which outlined measures to slash thousands of personnel, scrap the Harrier fleet and Nimrod spy planes and retire the HMS Ark Royal aircraft carrier.
The Ministry of Defence insisted it was not reopening the SDSR but said it was looking at balancing "defence priorities and the budget over the long-term".
"The three-month study is part of that work to ensure we match our assumptions with our spending settlement," a spokesman said. "We have made it clear that while the SDSR had made substantial inroads into the £38bn funding deficit, there is still more to be done."
The deep cuts unveiled last year set out the future shape and size of Britain's armed forces. Under the proposals, the defence budget is to fall by 8% over the next four years. The MoD is to cut its civilian personnel by 25,000 by 2015; Army numbers will be reduced by 7,000 to 95,500; Navy manpower will be cut by 5,000 to 30,000; RAF forces will be reduced by 5,000 to 33,000 and tanks and heavy artillery numbers will be reduced by 40%.
However, the MoD now wants to make further savings for the financial year ending in March 2012. Potential targets reportedly include HMS Illustrious, Britain's last surviving aircraft carrier, which is due back from a refit next year. Plans for a new fleet of armoured vehicles could also be singled out for the axe, the BBC suggested.
The review comes as Defence Secretary Liam Fox prepares to unveil the new military covenant which promises extra help for the armed forces and will enshrine their rights in law.
Dr Fox is expected to set out a number of enhanced services for the military, such as doubling the rate of council tax relief to 50% for those serving overseas, a £3 million boost for schools with high numbers of children from forces family and making it easier for seriously injured service personnel and veterans to access cut-price public transport.