Gordon Brown has been forced to admit he misled the House of Commons over defence spending, after an investigation by Channel 4 News FactCheck on 10 March.

Last week the prime minister told MPs defence spending had risen every year in real terms. But today he admitted the budget had in fact been cut for several years.

Channel 4 News FactCheck unearthed new figures after last week’s prime minister’s questions, which revealed Mr Brown had misled the House over defence expenditure.

Today he admitted spending had only gone up in cash terms – that is, ignoring the effects of inflation. “I do accept in one or two years, spending did not rise in real terms,” he said at the start of Prime Minister’s Questions.

Conservative leader David Cameron thanked Brown for his answer. “In three years of asking the prime minister questions I don’t think I’ve ever heard him make a correction or a retraction,” he said.