LONDON, July 21 (Reuters) - A 14 billion pound ($18 billion) class action lawsuit against MasterCard for allegedly overcharging more than 45 million people in Britain over a 16-year period was blocked from proceeding by a judge, MasterCard said on Friday.
The Competition Appeal Tribunal (CAT) has sided with MasterCard's argument that the claims were unsuitable to be brought under a so-called collective actions regime and has not allowed the case to go to trial, the company said.
"We welcome the Competition Appeal Tribunal's judgment refusing certification for the proposed collective action," a MasterCard spokesman said in a statement.
Had it been allowed to proceed, the case would have been the largest and most complex in UK legal history and would have tested the limits of the new Consumer Rights Act, which introduced U.S.-style "opt-out" collective class actions for breaches of UK or EU competition law in 2015.
U.S.-based litigator Quinn Emanuel Urquhart & Sullivan launched the case on behalf of adults in Britain after MasterCard lost a drawn-out appeal against a 2007 European Commission decision that ruled its fees were anti-competitive.
The case centred on so-called interchange fees, the charges levied by credit and debit card companies such as Mastercard on merchants' banks, which card companies say cover the costs of operating card services, security and innovation.
London-based Walter Merricks, a lawyer who once led the Financial Ombudsman Service group that handles consumer disputes with banks and who is the representative named on the class action, said he was considering an appeal.
He said he was surprised and disappointed at the ruling.
London's High Court ruled in January that MasterCard had charged interchange fees at a lawful level and without restricting competition in a similar dispute with retailers. ($1 = 0.7695 pounds) (Reporting by Kirstin Ridley; editing by Alexander Smith)