The 45 per cent tax rate introduced in the pre-Budget report could reduce the Treasury’s overall take, according to a study.

The Institute for Fiscal Studies, an independent think-tank, said the government’s expectation of raising £1.6bn ($2.3bn) a year from the first rise in the top rate since 1974 “is subject to an extremely wide margin of error and the possibility must exist that the measure could lose the government income tax revenue”.