The Defence Secretary has admitted the Government’s defence spending boost will probably total less than half of the £13.4 billion figure given by Sir Keir Starmer.

The Prime Minister told MPs on Wednesday that the uplift “means spending £13.4 billion more on defence every year from 2027” in a policy funded by cuts to the foreign aid budget.

Yet economists were quick to label the figure “misleading” and said a more accurate estimate was about £6 billion.

The decision to increase defence spending from 2.3 per cent of GDP to 2.5 per cent was brought forward after Donald Trump demanded Europe take more responsibility for its security.

Asked about criticism of the Government’s figures, John Healey told BBC Breakfast: “You can take it as a percentage of GDP, you can take it as cash terms.

“What Keir Starmer was talking about yesterday was the increase in hard cash that will be spent on defence in two years’ time compared to what’s being spent today.”

Asked whether the £13.4 billion figure would be correct if the defence budget did not increase in line with inflation, Mr Healey replied: “That’s a cash number.”

He continued: “In real terms, taking in inflation, it would be something over £6 billion. Either way, this is a big boost for defence.”