Emma Boon of the Taxpayers’ Alliance criticised the situation and said Treasury chiefs needed to act swiftly to close the loophole.
She told ClickGreen: “Taxpayers will be angry to hear that yet more Whitehall staff aren’t paying their fair share in taxes.
“The Treasury plans to issue guidance on this matter, to try to ensure all employees are paying their taxes, but this doesn’t get to the heart of the problem. HMRC and the Treasury will only ever be chasing their tails unless they look at more radical tax reforms.
“Simpler and lower taxes will cut the number of loopholes and reduce the incentive for well-paid Whitehall staff to try to avoid paying their taxes.”