Britain’s three intelligence agencies emerged as big financial winners from the comprehensive spending review on Tuesday – on the basis of what the government called a “severe and sustained” threat to the UK from terrorism.

The government, for what is says are security reasons, does not announce the separate budgets of the three agencies – the Security Service (MI5), the Secret Intelligence Service (MI6) and Government Communications Headquarters. But their combined budget is set to rise by an average 9.6 per cent a year in real terms over the next three years.