The first key hearing in the landmark class action against MasterCard gets underway today (18 January), with the Competition Appeals Tribunal set to determine whether the case will be certified and can proceed to a full trial.

The record-breaking £14bn claim was brought against MasterCard in September, on behalf of 46 million British debit and credit card holders over the company's charging of illegal payment fees. It is the first major US-style class action in the English courts, following the UK's introduction in 2015 of new legislation allowing 'opt-out' collective damages claims.

MasterCard, which is being advised by Freshfields Bruckhaus Deringer, has during the past decade been embroiled in a series of legal battles over the level of so-called 'interchange' fees it charged businesses on transactions between 1992 and 2007. These fees were found by European authorities to be unlawfully high. The plaintiffs, represented by Quinn Emanuel Urquhart & Sullivan, argue that part of the cost of these fees was passed on to consumers in the form of increased prices for goods and services.

MasterCard's cross-border interchange fees have already been found to be illegal—the company's long-running challenge to the European Commission's decision was finally put to bed by the Europe's highest court in 2014. Quinn Emanuel will now need to prove that the EC's decision also applies to domestic interchange—essentially, fees incurred when using credit cards in the UK, rather than abroad—and that consumers suffered damages as a result of those fees.

Quinn Emanuel partner Boris Bronfentrinker told The American Lawyer the firm is confident that the claim, which is backed by up to £40m in financing from Chicago-based commercial litigation funder Gerchen Keller Capital – its largest ever investment in non-US litigation – will be allowed to proceed. "The effect of MasterCard's criticisms and submissions would be to make the new collective action regime ineffective for consumers – the very group of people for whose benefit the regime was created."

A MasterCard spokesman said that the company "continues to disagree" with the basis of the claim. "We will be arguing strongly that these claims do not meet the set criteria for a collective action to proceed," he added.

Last summer, Sainsbury's successfully sued MasterCard over its interchange fees and was awarded £68.5m in damages.