Every single item on the concept car checklist has been well and truly crossed off with this, the Vauxhall Flextreme GT/E. It doesn't actually work, nor does it actually preview anything tangible, but it does boast astonishing green 'capabilities' and allow its maker to make straight-faced proclamations about some utopian corporate future.

The Flextreme GT/E turns its wheels using the same sort of drivetrain as the upcoming Vauxhall Ampera / Chevrolet Volt, prompting '175mpg and 40g/km' claims. If you've forgotten, that drivetrain is effectively a battery-electric hybrid, but one whose petrol engine - 70bhp in this case - acts only as a generator for the battery, never turning the wheels directly. The range is thus about 300 miles on a small tank.

It looks great too, doesn't it? There are some design cues taken from the Insignia and the Astra - most notably headlamps mimicking those cars' 'blade' motif. And, ahem, that's about it. The official release says it has a 'Vauxhall signature crease line' too.

The shape of the five-door, four-seat concept is dictated by function, though, with a low roofline (19cm lower than the Insignia) and active body panels to aid aerodynamics. Side spoilers lift at 30mph to direct air better across the body. The rear doors are of the 'suicide' type, and the cabin offers similar space to the Insignia.

Aluminium alloy and carbon composite body panels make sure that it's light, and power for its 40-odd mile electric-only range (before it has to tap into the generator) comes from a T-shaped lithium ion battery. It has 273lb.ft too, so the 0-62mph sprint is claimed to be completed in less than nine seconds. We'll get more information at Geneva.

Mark Nichol - 18 Feb 2010