Volkswagen has unveiled a 138bhp, 60mpg 1.4 petrol Polo that uses cylinder-deactivation technology to shut two cylinders down when they're not needed.

The Polo BlueGT also returns 108g/km of CO2, which is remarkable for the class. When mated to a seven-speed DSG gearbox the figures jump to nearly 63mpg and only 105g/km.

That's alongside a 0-62mph time of 7.9 seconds and a top speed of 130mph.

The system works in such a way as to shut down the two middle cylinders of the in-line four when using light throttle pressure, and Volkswagen claims that at a constant 30mph the savings are as much as 1.6 litres per 100 miles - not that many people will manage an uninterrupted 100 miles at 30mph.

To be precise the system works between 1,250rpm and 4,000rpm, at torque outputs of 18-74lb.ft. Any notable increase in throttle pressure reactivates the two deactivated cylinders, apparently imperceptibly.

The system is impossible to notice on the Bentley Continental V8, another VW Group car, so it's like that the Polo BlueGT's system will be just as refined.

In case you were wondering, all mechanical aspects of the activation and deactivation happen within a 13-millisecond to 36-millisecond window, which is very fast.

It's quite the looker as well, with very smart alloy wheels, lowered stance and special interior treatment that leaves it feeling much like the Polo GTI. In fact some features have been borrowed from that car, including the front and rear bumpers and rear spoiler. The instrument cluster has also been lifted from the GTI parts bin.

If it all sounds too good to be true, it might yet be. While sales commence on the continent in July, no word has been given on whether the BlueGT will be made in right-hand drive for the UK, and representatives refused to be drawn.