Concern over the ability of Britain's armed forces to protect the nation from a full-scale attack by a major military power such as Russia must be taken "very s

Major General Tim Cross spoke with Premier after a ten-page memo from newly-retired General Sir Richard Barrons to the Defence Secretary Sir Michael Fallon warned of a failure to prepare for the possibility of "risks" conspiring against the UK.

Maj Gen Cross said: "Russia is now a resurging power. China is obviously military power. If we were to find ourselves in a high-intensity war-fighting operation, we would be very pressed for all sorts of reasons, not least of which are numbers of equipment, numbers of people and so on."

The document by Sir Richard, which has been seen by the Financial Times, comes despite a pledge by the Government to boost spending on defence by almost £5 billion by 2020/21 and to adhere to Nato's goal to spend two per cent of GDP on defence until 2020.

Sir Richard said: "Capability that is foundational to all major armed forces has been withered by design. "There is a sense that modern conflict is ordained to be only as small and as short term as we want to afford - and that is absurd."

Maj Gen Cross, who served in the army for almost 40 years, said the Government's decision to have a military spending equivalent to two per cent of the UK's GDP did not go far enough.

He added: "You have to spend that sort of level - five per cent, give or take - over several years in order to bring back capability. Take nuclear submarines, destroyers or airplanes like the joint strike fighter, these are hugely expensive capabilities. We have some of the best equipment in the world but we don't have very many of them.

"What is the likelihood of a Russian attack on the UK homeland? Pretty slim at the moment. But the world changes. Defence is about strategic thinking, looking out over the next decade and deciding what your priorities are, what you believe is potential, probable or possible. Where do you draw that line? It's never easy."

Maj Gen Cross also rejected the idea Sir Richard's criticism was an example of "sour grapes" because he missed out on a promotion.

Click here to hear Maj Gen Cross speaking with Premier's Alex Williams: