The Mercedes-Benz CLA 180 d won't be the most affordable of the new CLA line-up, but it will be impressively affordable to run, thanks to excellent fuel economy. Fun, though? That's another story...

In the metal

We've already mentioned, in our review of the new Mercedes CLA 200 petrol turbo model, just how good looking the new CLA is, but it bears some repeating - while the old CLA was always good looking, but slightly messy in its styling, this new one is just super-smooth and George Clooney handsome. Mercedes' styling team has done a much better job, this time around, of avoiding the hatchback-with-a-boot syndrome, and the interior - lifting as it does the MBUX digital dashboard from the A-Class hatchback - is quite simply one of the best in the business.

It's also surprisingly practical - it's a little bigger than the old CLA in most departments, and interior space is actually pretty impressive. Even in the back there's sufficient room for a six-footer to get comfy (well, mostly comfy) and the boot is a practical 460 litres. Such things maybe don't occupy much the mind of the average coupe buyer, but it's nice to know that the CLA can walk the walk, as well as talk the talk.

Driving it

As noted in the CLA 200 review, the new four-door compact coupe is really rather lovely to drive, with excellent steering weight and response, a balanced chassis and a sense of genuine driving fun about it. Mostly...

We say mostly because, while that's all true for the petrol-engined models, for this most basic diesel model - expected to hold joint-best-selling status in Ireland along with the CLA 180 petrol turbo - that doesn't quite stack up. The chassis settings are basically the same, but the CLA 180 d is carrying an extra 70kg of weight, and that's all in the nose of the car. That makes itself felt, with distinctly sleepier responses from the steering, and a sense that the car understeers a little earlier, and more doggedly, than its petrol brothers.

That would be fine, but the engine itself fails to gel convincingly with the car, either. Although it has sufficient punch to back the styling up with decent performance, it does feel rather strained at the top end, and what's worse is that it doesn't combine well with the seven-speed twin-clutch automatic gearbox. It seems to hunt for gears too much, and the engine's high-rev blare is uninspiring.

On the upside, it is exceptionally economical. Mercedes quotes a whopping 78mpg on average for this engine, which is a bit steep, but in real-world conditions you could seriously expect to do better than 60mpg, which is hard to beat. It's a shame - if this engine were just more refined and made a happier combination with the automatic gearbox, it would be so much better.

What you get for your money

We still don't know the Irish prices for the CLA, but we do know that the basic petrol models will start from around €34,000, while this cheapest diesel will cost around €38,000. That's a big premium for an engine that's just not as satisfying as the petrol motor, so you'd have to be doing huge mileage every year to justify the extra outlay.

Summary

It's hard not to be disappointed with the cheapest diesel Mercedes CLA. That 1.5-litre engine is just not sophisticated enough to gel with the CLA's gorgeous styling, nor its equally gorgeous interior. On the upside, it's hugely economical, and you do at least get to enjoy one of the best automotive interiors around.