We don’t much like the current Volkswagen Polo BlueMotion, so we’re pretty pleased to hear that VW has a new one lined up. The fifth-generation Polo was introduced at the Geneva show this week, and will roll onto UK roads in October.

The new car is longer and wider – as new models always seem to be – but lower and, thankfully, lighter by 7.5 per cent, according to VW.

The current Polo BlueMotion uses a rough old 1.4-litre three-cylinder diesel developing about 80bhp, but the new Polo Bluemotion will gain a larger, 1.6-litre 90bhp common-rail TDI unit. Despite the beefier engine, and the larger body, the new Polo BlueMotion will achieve better combined cycle scores of 74mpg and 96g/km, a smidge under the 99g/km of the current, hair-shirt, airless BlueMotion 1.

The new car keeps to just five gears – presumably for weight reasons – and will offer the familiar intergalactic gear ratios in third, fourth and fifth.

There’s more to come. In 2010, a next-generation BlueMotion will gain a spanking new 1.2-litre triple. Power for this common-rail diesel will be down at just under 75bhp, but VW says it will hit 85mpg and 87g/km on the combined cycle. The company adds that this benchmark will be reached using stop-start technology and regenerative braking, on top of the under-body aerodynamics, long ratios, dropped suspension and low-rolling resistance tyres that are the bread and butter of the BlueMotion business.

While the numbers are impressive, the timetable isn’t. Why is it taking VW so long to fit stop-start to its BlueMotion models? It’s lagging behind Kia, for pity’s sake, which started building left-hand-drive versions of its Ceed ISG (Idle Stop & Go) model in January.

We can wait. We just hope that when it arrives, the new Polo BlueMotion is a big enough step up from the old one.