The retailer has won the right to deduct losses incurred from operations in other EU countries against its UK profits on its tax bill. Other retailers, including Asda and Carphone Warehouse, have claimed similar relief and were awaiting today's outcome.
It is thought M&S's victory could trigger a wave of similar actions. Hartley Foster, head of tax litigation at law firm DLA Piper Rudnick Gray Cary, said: 'As a result of this ruling, it will change the taxation system in this county and a number of other member state countries as well. There are about 150 to 200 other claimants who will be seeking their money. It will certainly cost the Treasury billions.'