Flash cars, gold bars and a superstar entourage... but what does Petra Ecclestone's £3billion husband James Stunt actually DO? Even his own billionaire father-in-law Bernie is baffled

The only stipulation for snagging an invitation to the frighteningly exclusive Ormeley Dinner is that one should be rich, influential – or, preferably, a combination of the two.

The annual eco-charity shindig, held earlier this month in sumptuous Bridgewater House in the shadow of St James's Palace, is the pinnacle of every self-respecting planet- hugger's social calendar.

Hosted jointly by Sting's wife Trudie Styler, posh conservationists Zac Goldsmith and Damian Aspinall, as well as Ruth Powys – girlfriend of Camilla Parker Bowles's late brother Mark Shand – it is an unquestionably ritzy affair.

Guests were entertained by Tom Jones and will.i.am, and dined on Sussex goats' cheese and 28-day aged beef, washed down with a rather pleasing Burgundy.

But while the event at the 19th Century property may have boasted a distinctly old money cast, it was dominated by one guest with decidedly new money connections.

Step forward James Stunt, colourful husband of Petra Ecclestone, the platinum-tressed daughter of billionaire Formula 1 boss Bernie Ecclestone. Art collector and businessman Stunt was determined, it seemed, not to be outdone when it came to some highly conspicuous acts of charitable giving.

Onlookers say that during a fund-raising auction, the 33-year-old self-made man dramatically summoned celebrity auctioneer Charlie Ross to his table before extravagantly joining the bidding on four £25,000 gold ingots – weighing 1kg each – donated by Stunt's own gold refining company.

In fact, he weighed in with a monster £200,000 offer – but only on condition the underbidder go higher still – then converted his bid into a donation. It was an impressively generous trick he then repeated when he ramped up the bidding for a weekend on a yacht! He also agreed to add £30,000 to top-up the final price for a sculpture.

By the time the evening was over, Stunt, who sponsored the event, was also its most generous giver, having pledged a cool £265,000.

Not, it seems, that he is short of a few bob, particularly if the fleet of five Rolls-Royces – most with private plates bearings his name – which were parked outside to ferry him and his all-male entourage to and from the party, is anything to go by.

Such conspicuous consumption is, needless to say, more than a bit OTT. Fellow guests say Stunt paraded around the whole night in a black coat, cutting a darkly rakish figure. No wonder his father-in-law, Suffolk trawlerman's son Mr Ecclestone, once famously branded Stunt a 'flash b*****d'. Yet with the extravagant behaviour comes a growing list of questions. The Mail on Sunday has learnt that even Mr Ecclestone is now asking how Stunt made all this money.

Nor is that the only puzzle. Why, for example, does a young entrepreneur best known for his dealings in the sedate world of fine art feel the need for such high-level protection wherever he goes?