In sworn affidavits we have evidence from the private secretary who paid Heather for pleasuring his billionaire master.

And we have testimony from Denise Hewitt, the ex-wife of the heir to the Berkeley Homes empire, that she joined Heather for lesbian games and group sex when they were both London prostitutes.

We can identify the madam who booked many of Heather’s rich and famous clients for a 20 per cent fee.

And we reveal that Heather’s vice trade wasn’t simply a moment of madness in her life. It went on for years.

Her secret sex games with international arms dealer Adnan Khashoggi took place in Spain’s Marbella and at the Lanesborough, Hilton, Dorchester and Grosvenor House hotels in London’s Mayfair.

She was paid amounts totalling £2,000 in sterling plus another 8,000 US dollars - currently about £4,400. But this was just a fraction of a secret fortune she amassed.

Heather earned a further £1,000 for a foursome with two other escort girls and an Arab prince at the Dorchester on London’s Park Lane.

A former escort girl named Petrina Montrose, who joined Heather for the Dorchester hotel orgy, told the News of the World: “Heather was a familiar face in our business.

“I worked with her when we were both hired for a party thrown by an Arab prince at the Dorchester.”

The 37-year-old, who now lives in Essex, said that she and Heather had been booked by a girl named Ros Ashley who also modelled swimwear under the single professional name ‘Ashley’.

Petrina continued: “It was a really lavish affair. There was a buffet of Lebanese food and Ashley was already there with a group of about six working girls, including Heather.

“The prince was tall and greasy and I wanted to leave but I knew that to get my money I’d have to have sex with anyone in the room who picked me. Still, Heather was bubbling over with enthusiasm.

“All the girls separated and, after a while, a blonde girl opened the prince’s bedroom door and beckoned me in. The prince was lying naked on the bed with his legs apart.

“The blonde girl lay on the bed between his legs, then I saw that Heather was already in there too. She was naked on the bed, kneeling next to the prince’s midriff. I took off my clothes and joined everyone on the bed. I knelt facing Heather and we performed oral sex on the prince. Then all four of us played together on the bed before the blonde girl who called me in had full sex with him.

“When we’d finished, Heather made no attempt to put her clothes on. Instead she started parading naked around the room, trying to impress the prince even more. At the end, Ashley paid us £1,000 each.”

Heather’s sex trade is also detailed by Abdul Khoury, who was Adnan Khashoggi’s private secretary from 1977 until last year.

Mr Khoury, who now lives in the Lebanon, has a great memory for detail. In precise language he told us: “I was responsible for organising all Mr Khashoggi’s arrangements, including meetings, travel and his social diary.

“One of my duties was to look after Mr Khashoggi’s guests, which would include looking after vice girls who were invited to see him. One was Heather Mills, who I know had sex with him on a number of occasions in return for money.…

“Sometimes Mr Khashoggi would make comments to me about the girls he paid to have sex with him.

“In Heather’s case I remember his remark that she had soft skin. And she was very athletic in bed. Mr Khashoggi was always very pleased with Heather’s performance.”

But Joanna wasn’t. It later became clear to those in Khashoggi’s circle of women that when all three of them were in the bedroom Heather had ‘tried it on’ with Joanna and suggested lesbian sex - and that it was much more than a performance for the arms dealer’s benefit.

Petrina Montrose recalled: “I was told that Heather has come on to a girl in a threesome and that the girl was upset. It’s completely out of order for one prostitute to make a lesbian approach to another unless it’s been discussed beforehand.

“But Heather seemed as interested in the sexual side of things - even lesbian sex - as well making money.”