Members of British law enforcement were part of a global operation to bring down, a website described by police as an online fraud shop.

They worked with Dutch law enforcement who managed to tap the website’s servers in the Netherlands to secretly listen to phone calls.

At one point, as many as 20 people every minute were being targeted by callers using technology bought from the site. Criminals – who found out about the site from adverts posted on channels on encrypted messaging app Telegram – used the site to buy technology that allowed them to mask their phone number.

This meant they could trick victims into thinking they were being contacted by their bank and persuade them to pass on personal details that allowed the fraudsters to steal cash.

One victim alone lost £3m, with the average loss being £10,000 for the 4,785 people who reported being targeted to Action Fraud. There are thought to be many more potential victims.

Of 10 million fraudulent...