A Conservative government would introduce ten-year plans for capital spending on defence, it has been reported.

The Financial Times reports that shadow defence secretary Liam Fox also told a gathering of defence industry executives last night that the party wanted to make it a legal requirement to have a strategic defence review every four years.

Fox told the meeting that a strategic review would be called within days of his entering government, but changes to spending commitments would be based on a full assessment of the UK’s national security needs.

Despite pledges from both David Cameron and the government to protect spending on the renewal of the Trident nuclear deterrent, there are fears in the defence industry that the dire public finances could lead to defence cuts.

Ian Godden, chief executive of the Society of British Aerospace Companies lobbying group, said that current defence expenditure was already too low. “Threats to our security do not go away simply because we are in recession.”

At the weekend, former defence secretary Des Browne conceded there was a disparity between the resources and commitments of the Ministry of Defence (MoD). “There is an order book which outstrips the department's capacity to pay for it - that's no secret."

Meanwhile, Lord Ashdown this morning claimed the defence budget faced a black hole of £9bn per year.

Ashdown was speaking on the day a major study of UK national security is published by an Institute for Public Policy Research (IPPR) panel co-chaired by the former Liberal Democrat leader.

The report, entitled Shared Responsibilities, also calls for the formation of a National Security Council, and an enhanced role in security for the Department for International Development (DfID).

On the Trident nuclear debate, Ashdown – though not speaking for the IPPR commission – said that a decision on its renewal should only be made after a full review of defence priorities, but added: “I can see no circumstances in which a rational review would lead us to the view that you should replace Trident with Trident.”