Still standing with remarkable confidence beneath the final approach to Heathrow airport, the crenellated Georgian mansion of Syon House in Isleworth, grand London residence of the Duke of Northumberland, has seen plenty of history.
The present house was remodelled by Robert Adam in the mid-18th century, but here once stood the immensely wealthy Syon Abbey, where in 1541 Henry VIII's fifth wife, Catherine Howard, was imprisoned before her execution, and where five years later the dead king's blood was lapped by dogs as his decaying corpse awaited burial at Windsor.
However, a more recent and less horrible history is being celebrated here today, at the seventh annual Salon Privé supercar show and concours d'élegance for classic cars and motorcycles. This three-day event is so extravagant and exclusive that Henry VIII himself would surely have approved, although he would probably have chosen to attend on Ladies' Day.
Sensual attractions abound, the more so if you are passionate about cars. "Wow!" exclaims a boy of about 10, beckoning his friend, "Look at that!"
"That" is a sexy souvenir of the Swinging Sixties, a bright green 1969 Lamborghini Miura that once belonged to Twiggy's boyfriend. It is perhaps a surprising attraction for a couple of schoolboys who might be expected to leave their fingerprints all over the contemporary supercars parked on the front lawn.
Yet there is more interest and variety in the back garden, where more than 100 classic cars and motorcycles vie for attention in the concours d'élegance, all claiming particular merit by virtue of beauty, rarity or individual history. Here is a delightful collection of pre-war Bugatti racing cars, there a line-up of no fewer than 13 brutal Ferrari F40s, opposite a mind-bogglingly valuable array of 10 Mercedes-Benz 300SL Gullwings, yonder a small estate of American and British shooting brakes, including a uniquely bizarre, green-and-gold, Vignale-bodied Ferrari 330 belonging to petrolhead rock star Jay Kay. Milling around are a couple of hundred more former schoolboys of advanced years, most shielding bald heads from the blazing late-summer sun with Panama hats.
One well-tanned and evidently eccentric old individual could be suffering from heatstroke: "My dear, England is such a beautiful country. It's just such a shame that the weather is not always like this …" Nearby, a slightly portly chap works the old boys' network with a recent acquaintance - "Oh yes, he might just be the very man to do your Maserati engine. Not the cheapest, of course" - before being interrupted by the eccentric, who stumbles past with a clearly uninterested female companion to praise a gleaming black 1961 Ferrari 250 GT SWB worth £2 million (Dh11.8m) or so: "It's a 1959 car, yes, a 1959 model, darling you really must remember that this is a 1959 model."
Shortly after noon, the crowd, such as it is, begins gradually to drift towards a buffet lunch among the gleaming supercars on the front lawn. Lobster, with summer fruits, cream and meringue to follow. There is so much lobster available that some guests eat three halves. The exhibitors have eaten little else for three days.
To the casual observer, there appears to be nothing very arduous about a concours d'élegance. Bring your expensive classic investment, in a closed trailer, to a garden party. Drive it slowly along a red carpet in front of a judging panel of automotive specialists, racers, designers and journalists. Hope to win a rosette or even "Best of Show". Have some more lobster. Meet friends, make acquaintances. Parade your personal success. Are they serving tea and scones yet?
There is some serious money here. Serious business, too. For the contemporary supercar exhibitors, an event such as Salon Privé is all about making contacts. A company such as Ford might launch a new hatchback at an international motor show where press and public fight to catch a glimpse of it, but at Salon Privé it is fair to assume that nobody is interested in mass-market motors; if you want to see anything from the Blue Oval you must peer beneath the engine covers of the Gulf Oil-liveried sports racing cars gathered behind the house.
Rather, the new cars on display are conspicuously upmarket: they include Bentley's Continental GT Speed, Overfinch's Range Rover GTS-X, Carrozzeria Touring Superleggera's Alfa Romeo-based Disco Volante and Aston Martin's Vanquish Coupe and V12 Vantage convertible, making its world debut alongside new models from little-known marques with almost impossibly small customer bases.
One such is Tushek Supercars, from Slovenia. It has yet to sell any of the 30 Renovatio T500s it intends to build, but knows where to find people prepared to spend €300,000 (Dh1.4m) - a modest sum, in this context - for a bespoke driving machine. "I am very pleased to come to Salon Privé," says company founder Aljoša Tušek, a gimlet-eyed former racing driver to whom the gentle concours competition is clearly anathema. "Britain is the most important place for this kind of super sports car, for the history of this kind of car. We will get customers here, and these first customers are very important for the reputation of the brand. We drove 22 hours to bring the Renovatio here for three days, and we will drive 22 hours back to Slovenia tomorrow. It is that important."
As he speaks, the boss of Rimac, a Croatian company showing the beautifully sleek, electric-powered Concept_One supercar glances enviously across the low white picket fencing that divides the lawn. While Tushek has been busy with interested punters, pretty girls and a hard-working press and PR operation, Rimac has drawn relatively little attention. It is not easy, when guests are naturally attracted to the outrageously dramatic Ferrari Enzo and FXX standing a few metres away.
The BMW stand appears quiet too, but has been making plenty of potentially profitable contacts. "Apart from being a lovely event in a beautiful setting, this is a great opportunity to speak to an eclectic group of enthusiasts," explains corporate communications director Graham Biggs. "The numbers aren't huge but the quality is very high. They all have the means to buy cars. We've sold quite a few and organised a good number of test drives."
It's not just cars, however. From a low-key collection of marquees promoting luxury goods, Michael Newton-Woof scans the crowd for would-be sailors. The Ventura company sells yachts, but not of a type that could make their way up the Thames as far as Isleworth. He points to one of the models on his stand. "A 100ft boat such as this will cost you about €9m [Dh42.3m]," he says, rather casually. "We reckon buyers will spend up to 10 per cent of their assets, so we are talking about people worth 100 million. It's quite possible they already have car collections and if they come here there is the potential to meet and make customers of them. In today's world you have to think out of the box to find new business. Salon Privé attracts high-net-worth individuals who are happy to spend almost £200 on a ticket, whereas The Boat Show costs less than £20 and is an ideal place to take the kids.
"In any case," he continues, "I like the cars and I like the organisers, who do a fantastic job. We're not going to sell anything straight off the stand; you must see a boat, sea-trial it and choose your specification first. But Salon Privé is perfectly timed: both the Cannes and Monaco Boat Shows take place this month, so we can take potential customers and show them 40 boats within a week."
Nearby, as the afternoon shadows lengthen, the concours event is reaching a genteel climax. In the shade behind Syon House, a tanned blonde woman sits in a little red open-topped sports car, the intense, crackling roar of its engine amplified by the adjacent walls. The scent of burnt oil is intoxicating as powerful pulses of exhaust gas flutter the expensive trousers of admirers standing a few metres behind. This 1950 Ferrari Barchetta 166 MM competed in the legendary Targa Florio and Mille Miglia road races. Its racing owner-driver, Sally Mason-Styrron, is no dilettante either, so there is no visible disappointment when she and husband Dudley appear on the red carpet to accept the "Best in Show" award.
Salon Privé co-director David Bagley cannot yet rest, but pauses for a moment to consider a question: What, for him, has been this year's highlight? His blue eyes widen as he runs both hands through his hair, momentarily lost for words. "Oh, there have been too many," he says. "The new manufacturers, the model debuts, the concours - the best ever - all these fantastic cars, the people, the weather … It's been … just … brilliant …"
Guests begin to drift away but one last ceremony remains. At 7pm, as the show closes, all the exhibitors are asked to start and rev their engines. Hard-edged, high-pitched yelps and barks punctuate a roaring chorus of growls, rumbles and retorts and for a minute or two, as a spine-tingling cacophony drifts away into the warm evening air, it must sound for miles around as if the great stone lions that guard Syon House have come alive.
Silence descends at last, then someone points to a jumbo jet approaching out of the darkening eastern sky at 1,500 feet, landing lights blazing, turbines whining. These huge airliners have been flying directly overhead, every 90 seconds, for the past three days - it is a tribute to Salon Privé's organisers that nobody has noticed them until now.
For more information, visit www.salonprivelondon.com