East Anglian firm Mills & Reeve has offered investors the chance to withdraw from a £5m corporate sponsorship scheme for polo matches in the wake of a barrage of criticism by a firm of tax analysts.

The move follows an announcement by financial analyst Allenbridge that it has reported the firm – part of the Norton Rose M5 Group – to the Department of Trade and Industry and the Law Society.

Allenbridge maintained the prospectus for the Insignia Cashbacked EIS issue contravened the Public Offer of Securities Regulations 1995 by failing to disclose planning restrictions at the polo venue, Ascot Park. It also believes a subsequent claim by Mills & Reeve, as sponsor of and solicitor to the scheme, that planning restrictions were about to be lifted, was misleading and a possible breach of the Financial Services Act.

But Mills & Reeve managing partner, Duncan Ogilvy, claims any deficiencies in the original prospectus have been corrected in the supplementary prospectus just issued on leading counsel's advice, which allows investors to withdraw from the scheme by Monday (September 30).

“A firm of our repute is not going to want to hide behind regulations,” he said, and then added that the opportunity to withdraw was “inherent in any supplementary prospectus”.

“As yet, people are not coming out in droves. We have still got over £3m out of a possible £5m and investors' confidence is where it has always been.”

He said he had heard from the Law Society to the effect that it was “not interested”, but he had not so far been contacted by the DTI.

Spokeswomen for both the DTI and the Law Society said they could neither confirm nor deny that an investigation was under way.

A spokesman for Allenbridge said the new prospectus had corrected some “significant inaccuracies” but he advised investors nevertheless to withdraw their funds.

“We would advise them to act immediately,” he said.

If the issue remains at around £3 million, Mills & Reeve stands to make about £210,000 – 7 per cent of the subscription in fees – plus 10 per cent of any net profit.

Insignia is a set of five EIS companies, each with a Mills & Reeve representative on the board.

Four are partners and the fifth is chief executive of the investment finance division, Martin Sherwood.