Volkswagen's Golf Bluemotion will cost from £17,325.
That means the Golf, which is capable of 74.3mpg on average and which has emissions of 99g/km of CO2, is £785 more than the standard 106bhp 1.6 TDI Golf on which it is based.
However, Volkswagen says a driver covering 10,000 miles a year will save over £120 a year in fuel costs alone.
The VW Golf Bluemotion is powered by the standard Golf's 106bhp 1.6-litre common-rail diesel engine, but has stop-start, regenerative braking, longer gear ratios and low-friction tyres.
It also has a styling kit to help cut drag and improve aerodynamics. This includes sports bumpers, sideskirts, a bigger rear roof spoiler and 15-inch alloys.
Weight-saving measures have also been employed to boost efficiency, with the spare tyre replaced by a tyre repair kit.