Britain’s Prime Minister David Cameron. Photo: Reuters

David Cameron could face “political problems” within his own party if he disregards a Nato target and cuts defence spending below two per cent of GDP, a Conser­vative former defence secretary said yesterday.

Liam Fox said many Tory MPs would find it “hard to swallow” if the Prime Minister allowed defence spending to fall below the target, while maintaining a pledge to spend 0.7 per cent of gross national income on aid.

Ministers are under increasing pressure from Tory MPs and senior military figures to commit Britain to meeting the Nato target to spend at least two per cent of GDP on defence beyond 2016. With deep cuts to Whitehall budgets to continue after May’s general election, Chancellor George Osborne is reported to have warned privately that it may fall below that level.

Fox warned against cutting defence spending at a time when international security is deteriorating and “one miscalculation” with respect to Russian aggression in eastern Europe could lead to conflict with Nato.

He told BBC1’s Sunday Politics: “I think this would be a political problem inside the Conservative Party because I think that people feel that the Government’s first duty is the protection of the United Kingdom and its citizens. We have to do what we need to make that happen. And I think that we have a commitment to Nato as part of our international treaty obligations to spend that two per cent.

“I think to say that we were willing to guarantee a proportion of GDP for international aid, but not willing to implement our commitments in terms of defence, I think a lot of Conservatives would find that difficult to swallow. Especially at a time when you can see the international security environment is deteriorating. What is happening at the moment, for example with Putin’s Russia, is really only one miscalculation away from potentially creating an Article 5 crisis that brings conflict to the European continent.”

Former head of the Army General Sir Peter Wall called for the major parties to make general election manifesto commitments on defence spending. He warned that a dip in defence spending to the mooted 1.8 per cent could see a reduction in funding for training or equipment.

Sir Peter said yesterday “We military folk would like to see manifesto commitments to levels of defence expenditure and it’s of concern to us that all parties would probably be content to have this conversation not happening at the moment. Implicit in what the current government was saying around the time of the Nato summit in Wales last year where we were suggesting that it was everybody’s responsibility around Europe to meet the two per cent of GDP for defence expenditure, implicit in that is the fact that that’s what we ought to be doing ourselves”.