Microsoft is set to face a multibillion-pound class action case brought by a former U.K. prosecutor over allegations that the tech giant illegally inflated the prices of software licenses, lawyers who plan to represent consumers said on Monday.

Alexander Wolfson, a former Crown Prosecution Service barrister, intends to file collective proceedings in the Competition Appeal Tribunal on behalf of thousands of public and private organizations in the U.K. that purchased software licenses. The software licenses include those for Office and Windows, according to his legal team.

Kate Pollock of Stewarts Law LLP, which is representing Wolfson, said that the case “could have a great impact on the fairness of the U.K.’s growing digital economy. Almost all organizations in the U.K. rely on the use of computer software, and it would be impossible for those affected by this harm to take individual action over the inflated prices we believe they were forced to pay by Microsoft.”

The claim alleges that Microsoft Corp. has breached competition law and that any organization in the U.K. that bought certain software licenses was overcharged as a result. The details of the alleged breaches have not been made public.

Wolfson, who has billed the case as one of the biggest class actions in the U.K., has notified Microsoft of his case in a letter before action.

The barrister must next obtain a Collective Proceedings Order from the tribunal for the claim to proceed to trial. The tribunal will then decide whether he is a suitable representative for the class and if the claims are appropriate to proceed collectively.

Microsoft did not immediately respond to a request for comment.

The tech giant, which is based in Redmond, Washington, is also involved in other legal battles in the U.K. It is locked in a long-running battle in the Competition Appeal Tribunal against software reseller ValueLicensing, which is suing Microsoft for £270 million ($355 million) over allegations that has stifled the supply of pre-owned licenses for its software in the U.K. and the European Economic Area.