Nat the ex-playboy set to be central character in Corfu holiday saga

When they were all partying together on Corfu this summer, it was the kind of scene Rothschild adores. Gathered around him was a concentration of power, financial and political, that few could equal. Deripaska is Russia's richest man; Mandelson was a European trade commissioner and, to add to the fun, there was his old friend George Osborne, shadow chancellor and a drinking pal from Oxford days when they were both members of the Bullingdon Club.

It would have surprised many, then, to see today that Rothschild had written to The Times to say that Osborne had discussed a donation to the Tory party from the Russian. He must have known how embarrassing this would have been for the Tories and his Oxford chum. But Rothschild seems to have been anxious to spring to the defence of his other friend, Lord Mandelson. The letter may be interpreted as a declaration of where Rothschild's true loyalty lies.

He has been tipped to become the richest Rothschild ever. His personal fortune is estimated at around £750 million (in pre-crash prices) and he is engaged in a number of major deals that could see this figure soar. One of his biggest projects is a plan to create a new Monte Carlo for the super-rich in an abandoned warship harbour on the coast of Montenegro.

It may be wondered how Rothschild, a scion of the great banking dynasty, became so close to Deripaska, a man whose business career was forged in the harum-scarum world of Russia's aluminium industry at a time when rumours of contract killings were part of the working day. In fact, the two became great friends after being introduced by Roman Abramovich, the former Russian oligarch and owner of Chelsea Football Club.

Rothschild is a Chelsea fan and when Abramovich arrived in London in 2003 he was invited into the directors' box. It led to business discussions and introductions. Rothschild had big investments in high technology and property companies - he was an early investor in lastminute.com - but his friendship with Abramovich helped concentrate his mind on opportunities in Russia.

He and his business partner, his father Lord (Jacob) Rothschild, were very optimistic about Russia.

They formed their own partnership, a company called JNR, and Nat has invested his own money in Russian companies. He owns a big share of Trigranit, which invests in Russian and east European property. Some estimates have valued it at up to £2 billion.

That would value Rothschild's share at around £300 million. It is not known precisely how much he is worth but few doubt he is heading for billionaire status. Four years ago, he bought a spectacular apartment in Klosters, the Swiss ski resort, where his hospitality is legendary among the world's business elite.

The idea of Nat creating his own legend may surprise those who knew him on the party circuit in New York and London in the Nineties. Here was a young man, heir to a family fortune worth around £500 million, who seemed not terribly interested in getting on in his own right. He would drink with his friends until dawn and start all over again the next night. At one stage it was feared he might never take his place among the Rothschild dynasty's immortals because he was spending all his time partying.

In his early days in New York, Rothschild met Tim Barrakett, an ambitious arbitrage expert who, like Rothschild, was in his mid-twenties. Barrakett wanted to start his own hedge fund and Rothschild put in his own money to become a 50 per cent partner.

They started with a fund of less than £4 million. Some of America's richest families began investing with them, and the business, which they named Atticus, grew swiftly to manage a fund of £7 billion. It is bound to have been affected by the downturn, but Rothschild has diversified widely, as his Montenegro deal with Deripaska demonstrates. No one is suggesting his path towards becoming the richest Rothschild ever is about to be blocked.