Smart ForTwo CDI

Astonishingly low CO2 emissions and amazing economy figures will make this new diesel-powered Smart a guaranteed sale hit, especially with the growing number of eco-minded car buyers. It’s just a shame that, as with the petrol model, the diesel ForTwo is hampered by a wooly experience behind the wheel – in town, it’s frustrating to drive.

It produces the lowest emissions figures of any non-electric car – but exactly how Smart is the new diesel ForTwo?

Until now, every UK version of the revolutionary city car has come with a petrol engine, as Smart bosses claimed that converting the left-hand-drive diesel – which has been on sale in Europe since 2007 – would be too costly. But with economy at the top of the agenda, the firm figures that derv power makes sense here, too.

And with stunning 85.6mpg claimed economy and 88g/km CO2 emissions, the ForTwo is definitely a credible choice from an environmental point of view. The figures translate into tiny fuel bills and zero road tax, so it will be easy on your pocket.

Visually, there’s little to mark the car out from petrol-engined variants. The top-spec Passion model we tried gets silver door mirrors, a matching radiator grille and alloy wheels, while several interior panels, as well as the dashboard, are trimmed in funky fabric material, rather than the cheap-feeling plastics of some rivals.

Given the Smart’s compact dimensions, it’s reasonably practical, too. There’s a storage cubby in the split-folding tailgate, a luggage net and a foldable passenger seat.

While the leather seats in our car were very upright, they were more comfortable and supportive than we expected. The problem is that, from behind the wheel, the diesel ForTwo is not the showstopper it could be.

Despite having 110Nm of torque available from 2,000rpm, the 45bhp common-rail engine has to be worked hard. This is mainly due to the awkward semi-automatic gearbox, which takes too long to shift up. While it’s not a problem on fast, open roads, it becomes annoying in the ForTwo’s typical urban habitat. Handling is decent, thanks to the short, square proportions, but the steering is heavy for a small car.

Nevertheless, an exciting driving experience is not what will attract buyers. The Smart is still as cool as ever, and low running costs mean the diesel is a good city car. Yet the likes of the Toyota iQ ensure that some of the ForTwo’s unique appeal is starting to wear off.