David Cameron has been told that his recent claim that the UK maintains a 'full-spectrum defence force' can't be justified, and that cuts to the budgets of the armed forces will inevitably lead to a shrinking of Britain's defence capability.
MPs on the Commons Defence Committee have issued a strongly-worded report, in which they take issue with recent statements by the Prime Minister on national security and question some of the decisions taken by Liam Fox at the Ministry of Defence.
The committee says: "Given the Government’s declared priority of deficit reduction we conclude that a period of strategic shrinkage is inevitable. The Government appears to believe that the UK can maintain its influence while reducing spending, not just in the area of defence but also at the Foreign Office. We do not agree."
The MPs are responding to last year's Strategic Defence and Security Review (SDSR), which took place at the same time as the more general spending reviews within government. The Armed Forces face a budget cut of 8% in real terms by 2015, and this led to the scrapping of both HMS Ark Royal and the RAF's Nimrod spy planes.
The SDSR was completed long before the current military operations in Libya, and some commentators believe the campaign against Gaddafi has exposed flaws in the SDSR's aims and objectives. But the Defence Committee says the MOD chiefs who'd given evidence to them had denied the armed forces were overstretched because of Libya.
MPs were particularly critical of the decision to scrap the Nimrod spy planes, writing: "We deeply regret the decision to dispense with the Nimrod MRA4 and have serious concerns regarding the capability gaps this has created in the ability to undertake the military tasks envisaged in the SDSR.
"This appears to be a clear example of the need to make large savings overriding the strategic security of the UK and the capability requirements of the Armed Forces. We are not convinced that UK Armed Forces can manage this capability gap within existing resources."
Malcolm Chalmers, director of research at the Royal United Services Services Institute, told HuffPost UK that the SDSR focused heavily on land forces - possibly at the expense of naval and air forces. He believes the Libyan conflict will lead to a re-assessment of the decisions made at the MOD a year ago.
He said: "At a time when the MOD is continuing to look at withdraw capabilities, any additional operations narrow the options for those reductions. Assets can't be in more than one place at a time. If the Libya campaign finishes this autumn then it'll be manageable. If it goes beyond that it'll also be manageable, but more risks will have to be taken elsewhere.
"I don't think there will come a point where it'll all fall apart, but you can't win a war from the air."
Tory MP James Arbuthnot, the chair of the Defence Committee, told Today on Radio 4: "While increasing our commitments by committing resources to Libya, we are reducing our resources available to deal with defence as a whole.
"We live in an increasingly unstable world with unrest and turmoil going on in Arab countries at the moment, and the problem with the SDSR is that it has left us with no contingency whatsoever."
The Armed Forces Minister Nick Harvey told the same programme: "It is a stretch, and nobody denies that. What we're doing in Afghanistan is now on a sustainable footing…we are coping with what we're doing alongside that. I don't accept that we're overstretched. This is within our capabilities but I do acknowledge that we are working people and kit very hard."