Businesses are being urged to attend a London seminar that could collectively net organisations hundreds of millions of pounds in wrongly paid National Insurance Contributions (NIC) on car allowances.

Tax and pension specialists Innovation Professional Services is working with lawyers Wright Hassall & Co and Hage Aaronson to put together a class action - also known as a Group Litigation Order - against HM Revenue and Customs (HMRC) which could be on a ‘no win, no fee’ basis.

Innovation Professional Services has a client to take the case to court, but wants to pool potentially up to 30 companies to mount the class action

The free seminar will take place at the London offices of Hage Aaronson on Monday, December 9. It will be repeated on Tuesday, December 10. Hosting the seminar will be top tax lawyer Graham Aaronson QC.

John Messore, partner and director of Innovation Professional Services, said: “The case is a once in a lifetime opportunity because the decision will be binding only on those taking part and so anyone who adopts a wait and see attitude is missing out forever. The view from counsel is that we have a very strong case.”

Messore declined to disclose how many companies were expected to be represented at the seminar, but hoped that a “large number” of financial directors and heads of tax would attend.

He said: “The expert view is that this is a case that should succeed and so anyone with a sizeable number of cash allowance drivers - over say 500 - should attend the seminar.”

The move is in the wake of the much-publicised Total People - now known as Cheshire Employer and Skills Development - case, which culminated in a victory in the Court of Appeal last year.

The company’s seven-year legal battle related to an NI refund claim based on the difference between the HMRC 40p per mile allowable rate (now 45p) and the 12p per mile paid by the employer plus an additional lump sum paid to the employees for using their private cars on business.

The value of the amount claimed was approximately £146,000 or around £1,000 per employee involved.

It has been estimated that the potential impact of the planned case on HMRC could be claims collectively amounting to between £200 million and £500 million.

To express an interest in attending the free seminar, for which the date has not yet been finalised, email gareth.roberts@bauermedia.co.uk, who will pass on your details to Innovation Professional Services.