“I’d quite like to just try and get a deposit together, to buy a house and stuff.”

After Mark* saw an advert for a financial trading website, he signed up to what he believed was access to an adviser who called herself Lilliana.

Through long phone calls together, Mark believed that he was making investments and that they were generating lucrative returns.

But when he tried to access his earnings, he found himself on a slippery slope that ended with him losing all of his life savings.

“You have to keep throwing more and more money into it before you get any back. It just seems mental.”

The Guardian’s senior business reporter Simon Goodley tells Michael Safi that Mark is just one of thousands of victims of an industrial phone-scamming centre in Tbilisi, Georgia - an operation that is believed to have duped people out of at least £27m.

After the leak of a million hours of recorded calls to the Swedish broadcaster SVT – which in turn shared the files with the Organized Crime and Corruption Reporting Project (OCCRP), the Guardian and other partners – the way that phone scammers work can be heard like never before.

Through the calls with Mark, Simon explains how scammers use a “good cop, bad cop” approach and pressure sales tactics to squeeze more and more out of their victims. Most people believe they are aware of the risk of being scammed, but Simon says the 6,000 victims identified on the calls come from all walks of life.

* Name has been changed