Brown admits defence spending mistake

Mr Brown made the assertion when he gave evidence to Sir John Chilcot's inquiry into the Iraq war, and repeated it at prime minister's questions last week.

But, responding to a question from Tory MP Tony Baldry, Mr Brown said: "Yes. I am already writing to Sir John Chilcot about this issue.

"Because of operational fluctuations in the way the money is spent, expenditure has risen in cash terms every year, in real terms it is 12 per cent higher, but I do accept that in one or two years defence expenditure did not rise in real terms."

Opposition leader David Cameron told him: "In three years of asking the prime minister questions, I do not think I have ever heard him make a correction or a retraction.

"The fact is, if you look at defence spending or defence budget cuts, there have been years with real-terms cuts and at last the prime minister has admitted it."

"The government is on firmer ground when it points out that the departmental budget is 10 per cent higher this year than in 1997, but FactCheck has established that Gordon Brown's central claim that the defence budget has gone up every year is fiction."

Asked how Mr Brown, who was chancellor of the exchequer for a decade, could have got the figures wrong, his spokesman said: "Budgets are pretty complex.

"This is one of the biggest, if not the biggest, budget in the UK government.

"One has to accept that the broad direction and the increase in defence spending has been absolutely clear and significant over the last 13 years," he told reporters.

He said: "When you look at the detail of a budget you are always going to have some specific issues but it is incontrovertible that defence spending has risen, in real terms, by 10 per cent since 1997, £8bn on top of that on Iraq and £9bn on Afghanistan."

The spokesman insisted that Mr Brown had "taken the first opportunity" to tell MPs about his mistake - but repeatedly refused to say when the PM first became aware of it.