The Government is being urged to cut hidden credit and debit card costs which are said to be "strangling" UK retailers, following a European court ruling against MasterCard.
EU judges upheld a European Commission decision banning MasterCard's "multilateral interchange fees" system - a charge on retailers for every card payment transaction they handle.
The Luxembourg court threw out MasterCard's appeal against the decision, confirming the Commission's claim that the way the system operates is a breach of EU competition rules.
The decision only applies to cross border credit and debit card payments in Europe, but the UK's Office of Fair Trading has been investigating such fees on domestic card transactions and the British Retail Consortium said it should now act.
BRC director general Stephen Robertson said: "I applaud the European Court for holding firm on its decision to end this unjustifiable tax on customers. This is an historic and highly significant decision on card charges for transactions between European nations but what comes next is crucial - and that should be fairer costs for customers and retailers whenever they pay by card."
He went on: "People deserve the same treatment on card charges when buying within the UK. Hundreds of millions of pounds are at stake. The Office of Fair Trading should follow this landmark European ruling with rapid action here."
CMS Payments Intelligence, a London-based specialist payments consultancy, said it expected UK Government action soon to bring down charges. "Hidden credit and debit card payments are strangling UK retailers and pushing up prices for customers," said company CEO Brendan Doyle.
Mr Doyle, who is handing a request for regulation to Chancellor George Osborne next week on behalf of more than 20 major UK retailers, went on: "The EU Court is the knight in shining armour for retailers and ultimately their customers too. The hidden and complex fees retailers face for accepting credit and debit cards have been ratcheted-up unfairly and consistently over a long period, and MasterCard has now lost its appeal to resist regulation of its powerful market position.
"While this ruling only applies to cross-border payments in Europe, for instance when tourists and business people use their cards within Europe, the principles set are much broader and it will open the door to greater regulation of hidden interchange fees domestically in the UK and Europe."
But MasterCard said the ruling would ultimately make payments more expensive for consumers. Announcing a further appeal against the decision, Javier Perez, president of MasterCard Europe, said: "Today's ruling, if it stands, would upset that sharing and tip the balance decidedly against consumers. It would also threaten the continued delivery of the most advanced electronic payment technologies in Europe which, in turn, are essential to facilitating business and driving economic growth."