Porsche Cayenne Turbo S, £118,455

I HAVE driven a Bentley Continental many times, and at no point have I ever thought, “Hmmm, I like the opulence and the strange sensations of cultured thuggery but I wish I could buy a version of this car that has a slightly lower top speed and is a lot less wieldy and considerably more expensive.”

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Bentley has recently launched a large SUV that covers all those bases. It’s called the Bentayga, and in essence it is a Continental that’s been ruined. It’s also a little bit ugly, and yet I guarantee that it will sell by the bucketload. In the Christian Louboutin and Chanel part of town you won’t be able to move for the damn things.

Lamborghini, too, is said to be working on a jacked-up supercar. It will, I understand, look like an Aventador on stilts, which means it’ll be like an Aventador, only slower, less economical and worse round the corners. That’ll sell as well.

The demand for leather-lined SUVs has gone berserk. I was at the Soho Farmhouse in Oxfordshire last weekend and the car park was hysterical. Everyone looked at me arriving in my Volkswagen Golf with open-mouthed wonderment. “How did you get here in that?” they exclaimed.

Almost everyone else had turned up in a black Range Rover. Indeed the Range Rover is now so popular that Land Rover’s sister company, Jaguar, has a rival — the F-Pace— arriving on forecourts this spring. It’ll be ideal, I should imagine, for all those who choose not to buy the Maserati Levante, another SUV, which will make its debut at the Geneva motor show in March.

It’s easy to see why all these car makers are so keen to make SUVs. The profit margins are huge, because you’re selling farmyard technology at farm shop prices. And when I say farm shop, I mean Daylesford.

A saloon car has to be fast and comfortable and refined, and all of this stuff costs millions of pounds to develop. An SUV just needs to be big and full of buttons. That costs 8p. For an extreme example of this in action, peer underneath America’s offerings. They’re just pick-ups with tinted windows. Rationally, then, SUVs make no sense. And yet . . .

I know that driving along in an SUV is like inviting all the poor people in your village to watch you build a bonfire out of tenners. I know SUVs are ridiculous and that they simply arm those who want us to go to work in a Google Igloo. But I must admit that my inner nine-year-old rather enjoys being at the wheel of a massive and turbocharged Tonka toy.

Which is why I was pleased when Porsche said I could use a Cayenne Turbo S over the Christmas holidays.

The Cayenne is an old car now. There is a city named after it in French Guiana. And a pepper. They’ve even found prehistoric cave drawings of it in various parts of the world.

In 2014 there was a small facelift that included the fitting of LED daytime running lights, but as soon as you step inside you know it’s old. The sat nav screen, for instance, in most modern cars is 16ft across, whereas in the Cayenne it’s the size of a stamp. And get this: to start the engine you have to put a key in a slot and then turn it. That’s as quaint as Anne Hathaway’s cottage.

The other thing that hasn’t really changed over the years is the styling, and that’s a bad thing. This is not a looker, and age has not improved matters one bit. It still appears as though the stylists were consumed by the idea of making the front look like a 911 and then had a tantrum and gave up completely with the rest of the car when their efforts failed.

There is no getting away from the fact that in one important respect the Porsche feels bang up to date. It is extremely fast. Bonkers. Insane. Eye-swivelling.

However, there is no getting away from the fact that in one important respect the Porsche feels bang up to date. It is extremely fast. Bonkers. Insane. Eye-swivelling.

Under the bonnet is a 4.8-litre twin-turbo V8 that produces 562bhp. And that makes it — since the 918 Spyder is sold out — just about the most powerful car Porsche builds. It’s so powerful, it holds the SUV lap record at the Nürburgring, having smashed the Range Rover Sport SVR’s time by almost 15 seconds.

It’s not just fast for an SUV, either. In a straight line to 62mph it’ll embarrass the driver of an Aston Martin V8 Vantage. Flat-out it’ll be doing as near as makes no difference 180mph.

My test car was fitted with the optional sports exhaust system, which produces the sort of deep, crackling rumble that frightens dogs. And it also helps to mask the sound of the fuel pumps, which, I presume, are a bit like a bank of firemen’s hoses.

To try to keep all this weight and all this power in some kind of check there are many buttons, all of which when pressed make the experience a bit less comfortable. I went for the softest setting, and — I’ll be honest — it wasn’t bad. Of course even in sporty mode it’s no 911 — it’s too high up for that — but then at least you aren’t sitting there thinking, “Oh no. I’m going to crash at any moment.” And that’s the best you can hope for, really, in a car such as this.

Bigger stopping distances. Lower cornering speeds. Thirst. These are the prices you pay for all the extra . . . um . . . er . . . height? Ground clearance? Off-road traction?

Well, yes, you get all that and a lot of clever electronic trickery, but the truth of the matter is that a car this big and this heavy is going to get stuck on a wet grassy hill. The only way round that is to fit it with off-road tyres, and if you do that, it’ll be a noisy, wayward nightmare on the way home.

Which brings us right back to the beginning. Why spend almost £120,000 on a Cayenne Turbo S — and that much again if you want it to have doors and a steering wheel and a radio — when it won’t work in the sort of off-road conditions that we get in Britain? Why not buy a Panamera instead? Or a BMW 530d? Or a Golf R and a Toyota Hilux?

Admit it. You want a big SUV because it’s part of today’s uniform. It tells people that you have a second home in the country and that you shoot. It says that money’s not a worry. All of this is human nature. It’s silly but it’s how we are.

The question is, however: having made the decision to buy a large SUV, should you buy a Cayenne Turbo S, with its quaint key slot and stamp-sized sat nav screen?

Well, yes, if you want the fastest SUV on the road. But bear in mind that within a year or so, once Bentley and Lamborghini are offering rivals, it won’t be.

Porsche Cayenne Turbo S specifications

PRICE: £118,455

£118,455 ENGINE: 4806cc, V8

4806cc, V8 POWER: 562bhp @ 6000rpm

562bhp @ 6000rpm TORQUE: 590 lb ft @ 2500rpm

590 lb ft @ 2500rpm TRANSMISSION: 8-speed automatic

8-speed automatic ACCELERATION: 0-62mph: 4.1sec

0-62mph: 4.1sec TOP SPEED: 176mph

176mph FUEL: 24.6mpg (combined)

24.6mpg (combined) CO2: 267g/km

267g/km ROAD TAX BAND: M (£1,100 for first year; £505 thereafter)

M (£1,100 for first year; £505 thereafter) RELEASE DATE: On sale now

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