When a shopper in France clicks “pay” on a UK website, the transaction looks simple. A checkout page. A confirmation email. A parcel on the move.
Under the hood, it is an international money transfer disguised as a domestic habit: a four-party card system moving value between a merchant, an acquiring bank, a card network, and an issuing bank — with a quiet toll built in.
That toll is interchange. And, since Brexit, it has become one of the most contentious prices in British payments.
On January 15, 2026, London’s High Court backed the UK Payment Systems Regulator (PSR) in a closely watched case brought by Visa,
