A British lawyer suing MasterCard for £14 billion (17 billion euros, $19 billion) over card charges accused the US financial giant on Friday of indirectly pushing up prices for all British consumers.

‘Our case is that businesses that had to pay these fees then naturally passed on their costs... to consumers,’ Walter Merricks from law firm Quinn Emanuel said on BBC Radio 4's Today programme.

Mark Barnett, head of MasterCard in Britain, told the BBC that card services had benefited consumers, adding: ‘We will be vigorously defending the case... We don't think consumers have suffered in any way’.

The law firm, which launched its collective action on Thursday, said MasterCard had imposed unlawfully high card fees between 1992 and 2007 and added the claim was ‘the biggest in UK legal history’.

The European Commission last year said the US credit-card giant overcharged customers and retailers, having already found rival Visa at fault over fees levied on card payments.

The Commission said it believed MasterCard was in breach of EU single market competition rules.

‘Many consumers use payment cards every day, when they shop for food, clothes or purchase anything online. We currently suspect MasterCard is artificially raising the costs of card payments, which would harm consumers and retailers in the EU,’ EU Competition Commissioner Margrethe Vestager said last year.

‘We have concerns both in relation to the rules MasterCard applies to cross-border transactions within the EU, as well as the fees charged to retailers for receiving payments made with cards issued outside Europe,’ Vestager said.