“In this market review we have provisionally found that the fees charged by Mastercard and Visa to UK businesses which accept payments from within the EEA are likely too high. In short, at this stage, we do not think this market is working well.

https://www.psr.org.uk/news-and-updates/latest-news/news/psr-provisionally-proposes-to-cap-cross-border-interchange-fees-on-credit-and-debit-cards-to-protect-uk-businesses/