Stephen William Boys, 58, Kelly Caton, 44, Jordan Kane Robinson, 23, and James Austin-Beddoes, 27, were found guilty of fraud, converting and transferring criminal property at Preston Crown Court and then sentenced to a total of 15 years.

All four were associates of James Parker, who masterminded the conspiracy from his home in Blackpool over a three-month period between October 2017 and January 2018. Parker, who died in 2021, identified and then exploited a loophole on the cryptocurrency trading platform which allowed him and his associates to obtain credits worth £21 million at that time.

Over three months, Parker extracted crypto assets worth £15 million from his trading account. His associates, Caton and Robinson, dishonestly withdrew £2.7 million and £1.7million respectively, from their accounts.

Parker’s financial adviser Boys worked with Kambi, a UK national based in Dubai, to convert the cryptocurrency into cash. It was then laundered through various foreign based online accounts.

They made money so quickly that Parker bought cars for strangers and gave away £5,000 vouchers to try to deal with the proceeds, Lancashire Police said.

A significant amount of the laundered assets have been returned or are in the process of being recovered on the behalf of the unidentified Australian cryptocurrency exchange.

Jonathan Kelleher of the Crown Prosecution Service says: “These offenders used the internet from the comfort of their own homes to obtain tens of millions of pounds worth of Bitcoin which did not belong to them. Cyber-enabled crime presents an increasing threat to international economic stability, as well as to honest individual investors in cryptocurrency.

“Painstaking analysis of vast amounts of digital material and collaborative liaison with the Australian and Finnish authorities enabled us to mount a successful prosecution against these criminals.”