Nine people have been convicted in connection with what is thought to be the UK's largest "boiler room" fraud case, which took £70 million from more than 1,000 duped investors, authorities said.
The gang splashed out on a lavish lifestyle of foreign homes, private jets, luxury yachts and fine wine after conning Britons into buying shares in what they thought were US firms, the Serious Fraud Office said.
But after the year-long sale restriction was lifted, they found the Madrid-based sales operation had sold them worthless shares in shell companies or inactive businesses.
The SFO said it had been investigating the fraud since 2007. Director David Green said: "Over 1,000 UK investors were defrauded by these criminals, who caused substantial financial damage and hardship.
"The victims were deliberately charmed, lied to and bullied, whatever it took to make them send their money to these criminals.
"The profits from this fraudulent scheme were used to fund lavish lifestyles featuring numerous overseas properties, wine collections, luxury yachts and private jet hire.
"The convictions mark the culmination of seven years hard work by a dedicated team of investigators, lawyers and accountants at the SFO, and close work with other agencies."
A boiler room fraud involves a business, often from overseas, persistently pushing the urgent sale of over-valued or even worthless shares in a company.
The investigation, codenamed Operation Steamroller, saw the SFO work with authorities in the US, Hong Kong and New Zealand.
The scheme's Australian mastermind Jeffrey Revell-Reade, 49, and Spain-based Briton Anthony May, 58, were convicted of conspiracy to defraud at Southwark Crown Court in London today, the SFO said, while R evell-Reade was cleared of a charge of corruption.
The SFO said it could now be reported that six other people were jailed in May 2013 in connection with the fraud, which spanned four years between 2003 and 2007.
Daniel Gooding, 39, from Brentwood, Essex, was jailed for seven years, while Shaun David Rumsey, 33, from Basildon, Essex, Philip Morris, 38, from Biddenden, Kent and Jon Steven Frank Emery, 36, from Romford, Essex, were jailed for five years. Ian Hughes, 34, from Hainault, Essex was jailed for four years and and Emma Farmer, 41, also from Brentwood, was jailed for three years.
The SFO said they formed the senior management and operations team for three Madrid boiler rooms and conspired with Mr Revell-Reade and Mr May to defraud investors.
A ninth defendant, Michelle Coleman, 62, from Brentwood was given a 21-month suspended sentence after pleading guilty to three counts of money laundering, the SFO said.