Former BBC Radio 1 DJ Chris Moyles claimed to be a second-hand car dealer in a bid to save up to £1 million in tax, a tribunal found.
Moyles and two others were named as taking part in a scheme called "working wheels" which counted "450 fund managers, celebrities and other high earners between 2006 and 2008" as members.
Members would claim back large fees they said they had incurred while working in the second-hand car trade.
A published judgment from the Tax Chamber of the First-tier Tribunal said Moyles's self-assessment tax return for the financial year ending on April 5, 2008, when he was presenting Radio 1's Breakfast Show, said he "had engaged in self-employment as a used car trader".
The judgement said:
The self-styled "saviour of radio" responded to the judgement against him on Twitter, saying he accepted responsibility for his mistake, and has learnt a valuable lesson.
Treasury minister David Gauke said the government was pursuing "these avoidance schemes" and advised taxpayers not to "fall for" schemes that reduce their tax bill so significantly. He said: