Having seen Jurassic Park, I never imagined that a dinosaur might be so smooth and agile on the move. They roar and lumber and snarl and scream, but never glide along with a sure-footed, yet graceful manner

It might not have had scales and menacing teeth, but the big car that I’ve been been driving was every inch the endangered species.

Volkswagen call it the Touareg, but for the sake of this article, we’ll call it the T-Rex, mainly because it’s easier to say and more apt. What you need to know is that this car – powered by a 3.0 litre V6 TDI engine and the biggest seller – is by no means the least economical vehicle in the T-Rex range.

No, if there’s an oil well in the yard, right next to the money tree, then you might as well opt for something properly thirsty and polluting, such as the 5.0 litre V10 diesel, or, better still, the R50 derivative, which does only 22.4 miles to the gallon, and spews 333 grammes of C02 for every kilometre.

This car, by contrast, does closer to 30 mpg, and gently exhales 278 grammes of C02 with every kilometre.

So, why do I imagine that it’s set to go the way of the diplodocus?

It’s because – and I suppose this is a good thing – we’re finally coming to terms with the fact that there won’t be much of a planet to off-road on if we continue to burn up fossil fuels with such passion.

More importantly, it’s starting to really hurt in the pocket, and that matters more to most than whether a few polar bears will still have chunks of ice to throw in the glasses of Coca-Cola which they drink whenever David Attenborough isn’t watching.

There are some amazing figures associated with the 3.0 litre V6 TDI T-Rex, and not all of them are good.

It’s quite surprising that something with the profile of triceratops can make it to 60mph in under 10 seconds. But worst of all – and brace yourself – is the fact that it now comes with an annual car tax burden of £400, which will rise to £440 a year from next year.

Buy one brand new after March 2010, and you’ll pay a first year tax rate of £950, followed by annual payments of £440. Whether you buy one now, or in 10 years time, when the footballer who first owned it has sold it to his agent, who passed it on to his postman, that expense of actually running the thing is always going to be prohibitive. The logical progression of taxing pollution to that extent is that only gazillionaires will be able to drive at all, and they won’t mess around with anything more eco-friendly than a Formula 1 car running on rocket fuel.

Priced out of the drives of ordinary people, cars like the T-Rex, which are bad for the planet, but not absolutely terrible, simply won’t need to exist.

Should we worry? Should we scour eBay for Sinclair C5s? Well, there was a time, not that long ago, when plastic bags hadn’t taken on beelzebub levels of evilness, when it was OK to celebrate vehicles like this. It is a truly awesome piece of kit, more exclusive and arguably better value than some of the cars from whom VW seek to steal customers.

It’s also a very nice place to be, with lots of leather trim, polished wood veneer, and loads of electronic trickery. It’s very capable, too, on and off the road, and looks far better than the ugly Porsche Cayenne, with which it shares a platform.

If you want to tow the caravan in something accomplished and shiny, then it’s probably still worth considering.

I loved it, but possibly couldn’t live with it, and certainly couldn’t afford to tax it, let alone buy one. Volkswagen agree that the Touareg is fast becoming a car for those who absolutely need it rather than a car for those who’d simply like one. As we were going to Press, they announced that they’d tweaked the 3.0 litre 16V diesel engine to make it common rail and more efficient, but it still sits in the same tax band.

There might be a BlueMotion version of the Touareg and there could even be a battery-assisted hybrid along soon, they say, but it’s more like that people will switch gear to something smaller, like the VW Tiguan, which has recently joined the range.

Take a good look next time you see something as cool and deadly as a T-Rex on the road, for one day soon, cars like this will only exist in strange theme parks where weird wheeled beasts roam the planet.

TECH SPEC

Model: VW Touareg 3.0 V6 TDI

Price: £32,640

0 to 62mph: 9.2 secs

Top speed: 125mph

Insurance Group: 16

Consumption: 27 mpg

Emissions: 278 g/km