Almost £31.6bn of tax revenue has been lost in the illegal trade of cigarettes, alcohol and diesel, according to analysis by a campaign group.
The TaxPayer's Alliance said over the past five years, up to £13.9bn has been lost in the illicit trade of cigarettes and about £4.8bn in diesel.
The group quoted analysis from HMRC figures, and said the shortfall is so big it could fund a 1.5p reduction in the basic rate of income tax.
They also said the taxman lost out on:
A spokesperson for HMRC said the UK tax gap - the difference between the amount due and collected - is among the lowest in the world.