First Drive: Mercedes-Benz C Class C250 BlueTEC SE 5dr Auto

So, Mercedes is having another crack at the 3-series then?

Not really. This time around the C-Class is more of a small S-Class. It's not trying so hard to be a sports saloon. Think comfort and safety, hand-in-hand with top-notch economy.

Can I have some numbers?

This is the C250 BlueTEC. Its 2.1-litre diesel makes 204bhp, surfing the car to 62mph in 6.6 seconds. Yet it's rated at 65.7mpg in the official cycle, for 109g/km CO2 (though this AMG line trim cuts about 2mpg and adds 4g/km or so). Mighty good figures for a big, quick automatic saloon.

So big, in fact, the interior and outside measurements are uncannily similar to the 1995-2002 E-Class. That's the one with twin round headlamps, now doing service as a late-night minicab near you.

How's it so comfy?

At the front it's now a four-link suspension, so the cornering forces can be managed separately from the shocks that affect ride. There's also an optional full air suspension, the first in this class. It quietly swallows pretty well every sort of violence the road visits on it.

The new C is quiet too, thanks to this engine being better-subdued than it was in past Mercs. It's a bit gravelly at idle but when you give it work to do it's well muted. And as noted, it's got decent performance, though you'll want to stick the autobox in sport mode to get much enthusiasm for sudden sprints.

How did they do that?

Powertrains apart, this is an all-new car: lighter and stronger. The body has aluminium castings around the front and rear suspension mounts, and high-strength steel surrounding the passenger cell. All the doors, and the roof, are aluminium too. The body alone is 40kg lighter than the old. It feels solid as a vault.

And they've engineered it for 4Matic in right-hand-drive this time. That also means we'll get the next version of the related GLK SUV. And in fact this architecture will form the basis of all Mercedes C-to-E sized cars from now on: the next E, CLS, C-Coupe, E-Coupe, estates, SLK and more besides.

Well whatever sort of metal we're looking at, how does it look in the metal?

Rather sleek. Not too baroque. Confident but not pushy. It's also exceptionally aerodynamic. One version has a grille with external shutters that flatten off at speed when there's no need for cooling air. That alone saves 0.01 cd, taking it down to 0.27. Mercedes says that compared with a car of the average 0.30 cd, that's the equivalent in real-world fuel saving to taking out another 100kg.

And inside?

There's masses of tech if you spec it, and a screen that guides you through all the options in a series of slick animations. It's easy to use too, with a quadruple-redundant layout of a big control-wheel, shortcut keys, voice activation and a new touchpad – which you can fingertip-write on, or use swipe or pinch or rotate gestures. Basically, if you can't communicate with this machine, you've probably got some sort of social disorder.

Spec all the driver-assist systems and it uses radar, stereo camera and ultrasound to figure out what's going on all around. It can look for – and take action to avoid – vehicles, people and other obstacles coming from pretty well any direction except outer space. It'll drive itself for about half-a-minute before telling you to get your hands back on the wheel.

OK, but I quite like driving myself, thanks awfully. Is all this new-fangled tech actually fun?

There's been no attempt to make the new C-Class superficially aggressive or sporty. It doesn't want to play with you like a 3-series – going on or off the power in mid-corner makes little difference to the attitude. You just steer and the car takes care of things, right up to some mighty impressive speeds. It doesn't feel exactly darty, but it's no barge, thanks to a significant weight cut since the last C-Class. The steering gets sharper on lock, and it's very progressive.

On the optional air suspension, it can also lower itself a little when you hit the sport button mode, as well as stiffen its adaptive dampers. This helps quell the roll and the understeer, and there isn't much understeer either.

Well this all sounds very grown-up.

Well yes, it's about comfort, ease of use and luxury. But modern luxury. It's not one of those old-fashioned luxury cars that immediately adds 10 years to you. In Mercedes-world, comfort means confidence too. You can drive it like you're chauffeuring a nun with a heart condition, and it's smooth and unperturbed. Or you can push it to its door handles and you still can't fluster it. It's got everything covered.