It’s funny, but I’d like to suggest today that the single biggest advance in a car’s ability to go round corners is not four-wheel drive or traction control or electronic damping.

It’s the cupholder. Think about it. Your car, technically, might have tyres by Evo-stik and treble wishbone suspension with pick-up points made of caviar and frankincense. But when you’ve an open can of Coke balanced precariously on the centre console you’re not going to explore the outer edges of the handling envelope. Or it will fall over.

The cupholder, in theory then, allows you to corner as the designers intended. But what about the phone that’s balanced on the ashtray? And the road map on the passenger seat? And the bottle of Coke that is wedged in one of the door pockets? Corner too quickly and all of these things will leap into the furthest unreachable recesses of the passenger footwell.

Worse. While your car is probably capable of generating 1g of lateral force in a bend, there’s no way you’re going to experience that when your £2,500 laptop is loose in the boot.

I had to empty my car yesterday and simply could not believe how much stuff came out of it. Endless CDs that had been given up for lost years ago. Tons of underwear (how?), a high-visibility safety vest, a shoeshine kit and enough loose change to fill the tank with petrol twice over. There was also what used to be a digital camera until I went a bit mad on the road from Oxford last week. Now it’s some wires.

And this, remember, is a two-seater sports car. So imagine how bad things are in a large estate. Which prompts a question: what exactly is the point of the five-door Audi S4 Avant? Audi probably think they’ve spotted a niche in the market here. A fast estate is something not offered by BMW. But there’s a very good reason why there’s no such thing as an M3 or an M5 shooting brake . . .

You buy a car like this when you have a labradog. And how do you think Fido will feel if you indulge yourself in the 4.2 litre V8 engine, the four-wheel-drive system and the sophisticated chassis? Sick, I should imagine.

This, I know from bitter experience, can blunt the enjoyment of a car. You may have a blast for 10 minutes but for the next two years you’ll be picking bits of semi-digested Winalot from the rear carpetry.

Of course, the dog won’t always be back there, acting like a giant four-legged traction control. Sometimes you’ll take the car to a garden centre and fill the commodious boot with delicate shrubs. Right, and you’re going home at mach 4 with them in the back, are you? Even something as simple as the weekly shop can keep a man in check more thoroughly than nine points, a pint-and-a-half of lager and a road-full of speed cameras. You load up at the supermarket with eggs and vegetables and if you’re not careful you arrive at home with an omelette.

I love the Audi S4. I love what it’s engineered to do. But I know in my heart of hearts that being an estate car it will never achieve half of its potential. And it’s the same story with the RS6 and the new Volvo V70 R.

This comes with two traction controls, two intercoolers, a turbo, four-wheel drive, 300bhp and perhaps the most advanced electronic nanny the world has ever seen, none of which will ever be used as you bumble back from the antiques market with a nicely refurbished 18th-century writing desk in the boot.

Again, I loved the S4. Finished in swimming pool blue with seats the exact colour of Dale Winton, it’s a lovely place to be and a lovely thing to behold. But it’s a bit like buying a 2,000-watt stereo when you live in a block of flats. You’ll never use the power.

And that brings me neatly onto the new Mercedes E-class estate. It’s available with the increasingly ubiquitous 5.5 litre supercharged AMG engine which will cause you to arrive everywhere with dog sick in your hair. So I’d avoid that one if I were you.

At face value you might decide to avoid the E-class altogether actually. The saloon looks just like a Honda or a Daewoo and things don’t improve with the estate. The new growth on the back looks the sort of lean-to one might find on the back of a miner’s house in Barnsley.

Then there’s the business of Mercedes service, which is run by people who don’t just don’t care. They are way beyond not caring. They hate you. They detest you on a cellular level. They don’t want to fix your car so much as smash you in the face with a tyre iron.

When they ring to say your car has been serviced and is ready for collection, what they mean is: “Your car is not ready, but we want you to have a wasted journey into town on the bus, you fat, capitalistic scumpig”.

I’m currently without my SL because of a puncture. The Mercedes helpline girl (Rosa Klebb) said she couldn’t possibly get a new tyre on a Sunday and especially not for an SL (doubtless thinking “because you’re even richer than the normal bastards I have to deal with, you f------ f---!”).

Eventually a dealer did send someone out with a spare wheel, but to punish me for spending so much he dropped the car off the jack. Really, it is impossible for a dealer network to be this bad by accident. I honestly believe the whole thing has been taken over by members of Class War.

Don’t, however, be put off. The E-class estate is so good, it more than compensates for the salesman who will be flicking Vs at you when you sign the order form, and gozzing in your coffee. It’s so good in fact that I’m giving it five stars.

Aesthetics first. To get round the ugliness problem you need to specify a dark colour, preferably black, and fit some drug dealer wheels. Then it becomes acceptable.

And now the engine. Forget anything that runs on petrol. I drove a CLK the other day with a 3.2 litre six and couldn’t believe how dreary and forgettable it was. It was the Ronseal of motors, faithfully doing what it says on the tin, but nothing more.

What you must have is a diesel, preferably the £36,000 3.2. I had this in my test car and couldn’t believe how much torque there was.

A little twitch of the toe at 80 on the motorway and it just lunged forward. There was no power, of course, nothing after the initial lunge. But when someone has done a long jump they don’t keep going and do the 100 metres, do they? I’m told the E-class 320 CDI was the fastest diesel car on the market until the V10 Touareg came along. But since the Touareg isn’t a car so much as a bulldozer, I reckon the Merc still has the title.

It is not only the fastest but also, by some considerable margin, the best. Every single time you press a button or move a lever, you reel back in astonishment thinking, “God that’s good”. I’m loath to use the American expression of “surprise and delight” but that’s what it does at every turn.

The interior lighting is as subtle as any London restaurant. The tailgate rises electrically, the boot is huge and under the floor you find two more seats that slot into place. Then there’s the satellite navigation, which is a doddle to use, and the distronic cruise control, which keeps you to the speed of the car in front, then accelerates when the coast is clear.

I think it is good at cornering too. But it never encouraged me to find out and that, above all else, is the mark of a truly wonderful estate car.

I liked the air-conditioned seats. I liked the fuel economy. I liked the brakes. I liked the space, the refinement, the air-conditioning.

I drove this car nearly 1,000 miles and not once did it ever even get close to being annoying. Just so long as it never goes wrong and therefore puts you in the dealer network, it will be as close to perfect as any car can be.

VITAL STATISTICS
Model Mercedes E 320 CDI estate
Engine type Six cylinder, 3222cc, turbo-diesel
Power 204bhp @ 4200rpm
Torque 368 lb ft @ 1800rpm
Transmission Five-speed automatic
Suspension (front) Four link suspension, MacPherson struts, coil spring, gas pressure shock absorbers. (rear) Multi-link independent air suspension system with integrated control stabiliser
Dimensions 4,850mm length; 1,822mm width; 1,496mm height
Tyres 225/55 R16
C02 194g/km
Fuel 37.2mpg (combined)
Top speed 145mph
Acceleration 0 to 62mph: 8.2sec
Price £35,860
Verdict Galling as it is to admit, this is a genuine five-star car and the best diesel on the market

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