The Ministry of Defense (MoD) is conducting a spending review expected to usher in a budget cut of up to 20 percent, part of government plans to reduce the budget deficit and safeguard Britain’s ability to borrow cheaply.

Britain is conducting a wide-ranging strategic defense review, looking at its role in the world and what military capabilities it will need to deal with future threats.

“We must get away from the over-centralizing tendency that has become the hallmark of the MoD in recent years,” Defense Secretary Liam Fox said in a speech. “They (defense officials) will also consider whether the current senior rank structure across the services is appropriate,” he added. Details of where the cuts will fall will be announced in October by the Conservative-Liberal Democratic coalition.

Britain’s helicopter fleet, which totals 490, could be cut by 20 percent under the defense review to save 4 billion pounds, London’s Evening Standard newspaper reported on Friday, citing a secret MoD memo. The MoD declined to comment on what it said was speculation. Last year, a parliamentary defense committee said a shortage of helicopters was undermining current operations and it was concerned that commanders had to use ground transport when a helicopter would be preferable.

The MoD’s budget this year is 36.9 billion pounds ($57.8 billion), and Fox said there was a shortfall in defense spending plans of about 37 billion over the next 10 years.

Analysts have suggested that army personnel could fall to 85,000 from about 102,000 currently, or that 30,000 staff could be shed from across the military. Fox denied media reports that branches of the armed forces, such as the navy and air force, would be merged to cut costs. He would not be drawn on a dispute between the MoD and the Treasury over who should pay up to 20 billion pounds to renew Trident, Britain’s submarine-based nuclear missile system. The MoD does not want the cost to come from its regular budget.

Britain’s armed forces, especially its ground troops, have been working beyond their intended capacity over the past decade in Afghanistan and Iraq, simultaneously fighting two of the biggest wars Britain has fought since World War II.

While in opposition, Fox’s Conservative Party accused the then-ruling Labour Party of failing to adequately fund the wars and said more helicopters were needed in Afghanistan.