The move appears to be designed to get round the upcoming credit card surcharge ban (13 January 2018).

Gareth Shaw, Which? money expert, said: “These new rules should finally put an end to consumers paying excessive surcharges and additional fees just for using their cards. Trading Standards must now make sure this ban is enforced across the board, and that businesses can’t find sneaky ways around it.”

The new legislation is designed to save consumers up to £473m a year in card charges and Which? is urging consumers to report firms wrongly adding surcharges to Trading Standards.

It added: “The government and regulator need to closely monitor the situation (including the card interchange fee regulation) and ensure the ban (plus interchange regulation) serves its purpose and has the positive impact for consumers originally intended. Essentially, it is important this new law does not result in price increases, minimum spend limits or even cards being refused by retailers.”

It said consumers should shop around to avoid retailers that make additional service charges, refuse to accept card or charge additional fees.