The UK payments regulator has warned Visa and Mastercard it will take action to tackle a lack of competition and transparency in the card payments market that it said was costing British businesses millions of pounds a year.

Visa and Mastercard, which account for 95 per cent of all debit and credit card payments in the UK, have increased the fees they charge merchants by 25 per cent above inflation since 2017, costing UK businesses at least ￡170mn extra a year, the Payment Systems Regulator said on Thursday.

The regulator’s plan to impose “remedies” on the card providers is the latest attempt to loosen the grip of Visa and Mastercard on the payments sector, following complaints about the fees from merchants and retailers, and calls for more competition.