The tycoon had been trying to rebuild his life with his 30-year-old girlfriend, who is a fashion entrepreneur and HELLO! blogger.
Scot Young with his fiancé Noelle Reno
His death on Monday afternoon comes almost a year after an extraordinary legal fight with his ex-wife concluded at the High Court.
Michelle Young won a £20million payout but insisted her ex-husband was worth billions and had hidden his money.
In 2009, after the couple had separated the financier offered her a £300 million settlement that would have helped care for their two teenage daughters Scarlet and Sasha. However, the following year Scot said that he had been bankrupted by a disastrous business deal.
Noelle stood by him in January last year when a judge jailed him for six months for refusing to disclose full details of his wealth to the court.