Frankfurt 2011: Mercedes F125!

Its name features an italicised exclamation mark. It has gullwing doors. The sat-nav works via a series of "intuitive hand gestures". It is, of course, a concept car. But rumblings around camp Mercedes suggest that there's a tad more to the F125 - built to celebrate the manufacturer's 125th anniversary - than a look-at-me show queen.

It's a hybrid. But instead of the usual petro/electro mix, thrust comes from a high-voltage lightweight lithium-sulphur battery and F-Cell hydrogen-powered motor. And as Mr. James May opined after driving the Honda Clarity, hydrogen is the future. Or at least could be.

See more pics of the Mercedes F125 concept

It's also one of few luxobarge concepts to align itself with emission-free motoring. And because it's not designed as a fiddly little urban runaround, it has a range of 1000km, seating for four actual humans - though the rear bench looks more like a 31st century chaise longue - and air suspension (the first electric car with air-ride, no less). Which sounds useful.

But will any of this reach production? Possibly. But not for a while. Head of Mercedes-Benz cars, Dr. Dieter Zetsche, explained how hydrogen's a big part of the firm's future, claiming that MB's currently working with legislators to build an infrastructure able to support vehicles of its ilk.

Zetsche says: "Hydrogen contains more energy per weight as any other fuel. The technology's there, but we need the service stations. It's the chicken-egg problem and to support hydrogen there must be a paradigm change... But if we offer these new, alternative technologies, I don't see why hydrogen couldn't be the answer for us."

And there is also word that the exterior is not just for show: parts of the design are mooted to turn up in the new 2013 S-class.

Reckon Mercedes will lead the hydro-charge, TopGear.commrades?