Celebrities including Wayne Rooney and Anne Robinson could face massive tax bills from the Inland Revenue, following an investigation into Ingenious Media's Inside Track fund.
According to a Mail on Sunday investigation, dozens of celebrities were among the partners in the scheme which began in 2003-4, investing sums from £160,000 to £1.4m.
BBC presenter Jeremy Paxman, film-maker Guy Ritchie, pop star Peter Gabriel and Labour peer Lord Hollick were also investors.
However, the Revenue has now contacted some of the investors in the scheme with tax demand for tens of thousands of pounds.
Ingenious has reportedly written to all affected investors informing them of the HMRC investigation. The letter states HMRC believes "the partnership was not trading on a commercial basis and so [partners] have underpaid tax". However, Ingenious has told investors it does not believe this is correct.
Documents seen by the Daily Mail show other celebrities have invested large sums in schemes run by Ingenious beginning in other years, although it is not clear if these schemes are being investigated too.
Ingenious, founded by chairman Patrick McKenna, has over the past 10 years raised some £5bn for the film industry, investing in films including Avatar and Night At The Museum.
Mr McKenna was unavailable to comment on the investigation but reportedly told investors he believes HMRC is 'wrong in law' on the issue.
The regulations regarding film investment have been tightened in recent years. Any tax benefit is now retained by the film company, not wealthy investors.
An HMRC spokesman told The Mail on Sunday: "The tax breaks for investment in British films has been significantly reformed so that the relief goes where it was always intended to go - those who produce films and employ talent.
"The loopholes which allowed the tax relief to be abused with no benefit to the film industry have been closed. If we find evidence of abuse we will take steps to put things right."
A spokesman for Ingenious says: "Our film partnerships are not tax schemes, they are film schemes. The schemes have a cash-flow benefit because investors do not have to wait for years over the life cycle of a film to get their money back.
"HMRC is trying to distinguish between bona fide investment funds and out-and-out tax schemes. We are not in the business of generating tax schemes. Everything we do has a commercial engine attached to it.
"It is standard practice for HMRC to enquire into schemes where tax relief has been claimed on losses. We welcome the scrutiny."
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