On this morning's episode of the Cheat Sheet with Ridge And Frost podcast, presenter Wilfred Frost explained the laws around insider trading, and how Peter Mandelson could have fallen foul of them in his communication with Jeffrey Epstein.
He said: "You have to have material, non-public information - so information that's relevant to the markets that other people don't have.
"And either you encourage someone to deal on it, which is a bigger crime, or simply you disclose it. You don't have to be the person then profiting from this information if you disclose it and you are aware it is sensitive.
"It's a crime, by the way, that can lead to up to 10 years in jail in the most extreme circumstances."
Explaining how it relates to Lord Mandelson, Frost said people are pointing to "two big examples".
"In 2009, he seemingly shared internal advice to the prime minister, Gordon Brown, about whether the UK should sell off up to £20bn of financial assets to try and ease the debt burden," Frost said.
"Let's remember this was the peak of the financial crisis - there was a lot of pressure on markets all around the world. And similarly, seemingly leaking plans for a £500bn bailout the day before it then happened.
"This is, on the surface, material non-public information."
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Mandelson has previously said: "I was wrong to believe Epstein following his conviction and to continue my association with him afterwards. I apologise unequivocally for doing so to the women and girls who suffered."
In an interview with The Times carried out last week but published on Monday, Mandelson referred to a "handful of misguided historical emails, which I deeply regret sending", and described Epstein as "muck that you can't get off your shoe".