Marcia Illingworth has joined a growing band of victims of credit and debit card fraud. After making an online transaction with a small company, she found her details had been used to charge a pay-as-you-go phone to her debit card, then £600 ($1,058, €744) in charges. The card and phone company sorted things out but she felt “incredibly violated”, she says.

The problem of card fraud is particularly acute for smaller retailers. They may lack the funds and time to keep up to date with changes in the security threat, while research suggests many are confused over who is liable for online fraud: retailers often believe, wrongly, that liability resides with banks.