The charity’s latest research shows Buy Now Pay Later (BNPL) shoppers were charged £39 million in late fees in the past year.

Of those who were referred to a debt collector for missed payments, 96% experienced a negative consequence. They reported at least one of the following: sleepless nights; ignoring texts, emails and letters in case they were about debts; avoiding answering the door; borrowing money to repay the debt; or their mental health getting worse.

Yet the charity found that not one of the BNPL checkouts on leading retailers’ websites warned people they could be referred to debt collectors for missed payments. Instead this was only flagged in the T&Cs on a separate page, if at all. Citizens Advice conducted mystery shopping at 100 leading retailers and found 38 offered BNPL, with 22 offering more than two BNPL options, meaning there were a total of 74 BNPL checkouts.

The research also found that out of those offering BNPL, only 11% warned shoppers they were taking out a credit agreement, the remaining 89% put this information in the small print or T&Cs.

Citizens Advice asked the BNPL firms featured in the research if they ever referred customers to debt collectors. Klarna, Clearpay, Laybuy and Openpay confirmed they do this as a last resort. Splitit said it doesn’t. PayPal refused to comment.

Citizens Advice is calling on the Treasury to urgently regulate BNPL as it fears shoppers have been left unprotected and ill-informed during the rapid expansion of the sector.

Dame Clare Moriarty, Chief Executive of Citizens Advice, said: “The sheer number of shoppers facing debt collection is startling. We know from our frontline advisers just how much stress this can cause.

“A seamless Buy Now Pay Later checkout process should not mean shoppers have to dig around in the small print to find out they’re taking out a credit agreement, and could be referred to debt collectors if they can’t pay. The warnings should be unmissable.

“The Buy Now Pay Later industry has exploded and we need consumer protection to keep up with the changes in the way we live. We hope the Treasury can keep pace.”

Citizens Advice urges anyone who has been contacted by debt collectors to get free, independent debt advice. Contact Citizens Advice for more information and see our Debt and Money advice.