The UK Competition Appeals Tribunal (CAT) has ruled that the £14bn class action lawsuit against MasterCard for overcharging 46 million customers can not be processed as a class action law suit.

In its order, the court said that it would not grant the necessary collective proceedings order, a type of US-style class action, for the litigation to continue to trial.

The CAT’s decision will bring significant relief to MasterCard, as the case is touted to be the largest and most complex case in UK legal history.

Welcoming the UK’s CAT decision, MasterCard said: “We welcome the Competition Appeal Tribunal’s judgment refusing certification for the proposed collective action.”

The case was filed by a US-based law firm, Quinn Emanuel Urquhart & Sullivan, after MasterCard’s appeal against a European Court of Justice (ECJ) ruling was rejected.

The lawsuit was filed in 2016 on behalf of the million of Britons accusing MasterCard for illegally collecting interchange fees over a period of 16 years.

The latest verdict from the CAT follows a High Court ruling announced in January which pronounced that MasterCard’s chagrining of interchange fees was lawful and not anti-competitive.

The CAT ruling will not put an end on the class action case against MasterCard, as the London-based lawyer and named representative for the class action, Walter Merricks, said that he is considering to file an appeal against the ruling. Merricks further said that he was surprised and disappointed by the ruling.

Merricks added: “I am concerned that this new regime, designed to benefit consumers, may never get off the ground. The granting of the collective proceedings order in this case would have allowed 46m consumers to recover the losses caused to them by MasterCard’s proven illegal conduct.”