Anthony Constantinou, 41, was found guilty on Monday after a seven-week trial at Southwark Crown Court.

He absconded during the trial and an international arrest warrant has been issued to trace him. In his absence he was found guilty of fraud by false representations, fraudulent-trading and money laundering.

The case involved an investment scheme known as the ‘Managed Account’, which was provided mainly by a company referred to as CWM, Capital World Markets or CW Markets.

From late 2013 to March 2015, CWM offered investors very high returns of around 5% per calendar month - 60% a year - on allegedly risk-free transactions on foreign exchange markets.

More than 250 investors were attracted to the scheme by the promise of high rewards. They were told that CWM had special ways of FX trading that gave it access to preferential prices and meant it would always make money on trades. The claims were lies.

There was usually a minimum investment of £50,000, rising to £100,000 later.

In the classic Ponzi-style scheme, investors’ returns were paid directly out of the investments and the rest of the money was spent.

Millions of pounds were lavished on the image of CWM, including sponsorship deals designed to make the company look successful and thereby attract yet more investment, and millions of pounds were paid for the benefit of Mr Constantinou who controlled the funds.

Emma Beazley of the CPS said: “This was a callous scam targeting members of the public.  Many people lost their hard-earned money because of Constantinou’s greed and false promises in this fake investment scheme.”

Detective Inspector Nichola Meghji, of the City of London Police, said: “This has been a long-running and complex investigation. Anthony Constantinou is a career criminal who is out to make as much money for himself as possible, with no regard for anyone else.

“Throughout this lengthy investigation, Constantinou has continued to try to deceive officers and deny any wrongdoing. In a further move to deny any involvement in this case, he decided to stop attending his trial.

“We are glad that the jury has seen through his lies and found him guilty.”

Mr Constantinou will be sentenced later.