The US Supreme Court late on Wednesday handed down a long awaited judgement which upheld the appellants’ claim in the FII group Litigation v HM Revenue & Customs.

The judge ruled that a section of the Finance Act 2007 has been in breach of EU law. The court specifically found that the Treasury breached European law by retrospectively blocking tax refund claims. A ballpark figure of up to £5bn of revenue is at stake in the litigation, which may have to be refunded to six multinational companies.

One of the key test claimants, the British American Tobacco Group, could receive an estimated refund of £1.2bn.

HM Revenue & Customs said following the judgement: “HMRC is currently considering the implications of this complex judgment carefully. We will be vigorously defending those parts of the decision still under appeal.”