Mercedes S 63 AMG coupé, £125,595

WE HAVE been told many times in recent months that driverless cars are now being developed and we’re all dimly aware, if we are paying attention, that there are many issues to be addressed before they are allowed onto the roads. Quite apart from the technical hurdles, which are legion, there are ethical conundrums too. For example, what will a driverless car do when, in an emergency, it is presented with a choice of whom to kill? You, its owner? Or the bus queue into which it must plough if it is to save your life?

And then there’s the biggest question of them all: what’s the point? You send your driverless car into town, it finds a parking space, slots in neatly without scraping itself against anything and . . . and . . . and then what? It can’t go into a shop and pick up some milk, can it?

Search the used Mercedes S-class on driving.co.uk

For a driverless car to be useful, it must, first and foremost, be a car. And if it’s going to be a car, which is a personal transportation device, you may as well do the driving. Because driving is not taxing or difficult. You just have to sit there and miss stuff.

I had a taste of driverless-car motoring last week when I spent the week with a Mercedes S 63 AMG coupé. This car had the lot. It could steer down a road with no input from me. It could sense an impending accident and lock its brakes to activate the seatbelt pre-tensioners; it could also identify pedestrians on the pavement and anticipate what they would do next, and then take avoiding action to miss them. My job was simply to get out at the other end, looking as relaxed as that smug chap from the old Rothmans adverts.

But I never did because, actually, the cleverest electronics are not as clever as even the stupidest human.

Let us take the humble parking sensor as an example. In any city centre parking manoeuvre, they start wailing and barking when they are 3ft away from an obstacle. This is no use at all. You’re always 3ft from something when you’re parking. You need a reminder when the gap’s down to 3mm.

This is the problem that blights the Mercedes. Yes, it’s very clever that it can “read” the speed of the car in front and maintain a constant gap. But how does the driver of the car in front know you want to overtake when you are being stationed by electricity three miles off his rear end?

And then there was the last-minute change of direction that I needed to make to avoid one of the nutty paps who remain on my tail. I had seen the car on my nearside and I knew for sure I could nip in front, but the Mercedes decided it knew best and took control of the steering and the brakes.

I blame the world’s lawyers for all of this. Mercedes knows that it could bring the tolerances down to reasonable levels but if it did so, and there was a crash, any QC worth his considerable weight could summon a galactic bout of mock incredulity in a courtroom. “Do you expect us to believe that this car could steer through a gap with just” — snort — “3mm to spare?”

I’m afraid that after just a couple of days I turned off all of the drive-by-wire stuff and just used the Mercedes as a car.

There has always been a coupé version of the S-class and it’s always been called the CL. But for reasons that are entirely unclear to everyone outside the Mercedes marketing department this is called the S-class coupé. That may be technically correct, but I can assure you it sure as hell neither looks nor feels like a two-door version of the big Berlin taxi.

It looks wondrous. My test car had silly red brake callipers and optional Swarovski crystals in both its daytime running lights and its indicators, but these aside, it was a menacing blend of power bulges, skirts and the sort of brushed-zinc look that you find in those million-pounds-a-yard kitchen shops on Holland Park Avenue, in west London.

Inside, there was quilted leather and a sense that you were in the first-class cabin of a Far Eastern airline. It’s the sort of car in which you say “Mmm” as you settle down and close the door. The seatbelt is even handed to you by a butler. He never brought any nuts, though. Black mark, that.

Eventually, though, when you’ve stopped going “Mmm” and turning all the electronic paranoia off, it’s time to go for a drive — and it’s exactly what you’d imagine. “Cadderberry luggzury” (as the chocolate ads used to say) with a hint of chilli pepper.

Of course there are buttons to make the whole car uncomfortable — you even get one that makes it lean the wrong way in corners — but if you leave all this alone, you get a fast, comfy coupé that rumbles when you give it the beans and hums when you don’t. It’s nice.

Apart from the steering. There’s nothing wrong with it, naturally. It doesn’t suddenly stop working and the wheel doesn’t abruptly become red hot. But just occasionally you do wonder if it’s connected up as well as it could be. I have a similar issue with the mildly hesitant throttle.

But here’s the main problem I have. For quite a lot less you can have a BMW M6 Gran Coupé, which is even better- looking and comes with two more doors. It doesn’t have the driverless toys, but you don’t want them anyway. And it won’t cruise quite as well, but on the upside, it is much, much more exciting.

If that’s not what you want, fair enough, but that’s where the Bentley Continental GT enters stage left. This has the Merc’s luggzury and the quilted leather and, if you go for the V8, the exhaust bark as well. Plus it is a Bentley, and that counts for more than a Mercedes badge.

All three cars are good-looking, fast two-seaters with space in the back for very small people on very short journeys. And all will depreciate like a chest of drawers falling out of a tower block.

If you really do like driving — and if you’ve read this far into a motoring column, I have to suppose you do — then the BMW is the obvious choice. It is magnificent and snarly and balanced and all the things you crave. On a dirt road in Australia last year, with the sun going down after a long, hot, beautiful day, it provided me with what I think was the nicest drive of my life.

As a driver’s car the Bentley is not — quite — in the same league as the BMW, but what you lose in cornering and braking and acceleration, you gain in the “Ooh, that feels nice” moment when you close the door.

Which leaves us with the Merc. It is stuck between a rock and a soft place. And I’m not sure that’s a very sensible place to be.

Clarkson’s verdict ★★★☆☆

Designed like it’s driven – on autopilot

Mercedes-Benz S 63 AMG coupé specifications

Price : £125,595

: £125,595 Engine : 5461cc, 8 cylinders

: 5461cc, 8 cylinders Power : 577bhp @ 5500rpm

: 577bhp @ 5500rpm Torque : 663lb ft @ 2250rpm

: 663lb ft @ 2250rpm Transmission : 7-speed automatic

: 7-speed automatic Performance : 0-62mph in 4.2sec

: 0-62mph in 4.2sec Top speed : 155mph

: 155mph Fuel : 28.0mpg (combined)

: 28.0mpg (combined) CO2 : 237g/km

: 237g/km Road tax band : L (£860 for first year; £485 thereafter)

: L (£860 for first year; £485 thereafter) Release date: On sale now

Search the used Mercedes S-class on driving.co.uk