Mercedes B-Class F-Cell - Merc's Cell out - 2009

OK, it’s not quite as dramatic as the BMW VED concept, but here’s a slice of green German goodness that’s a heck of a lot closer to production.

This is the B-Class F-Cell, a hydrogen-powered version of Mercedes’ city car set to launch in Europe early next year.

A couple of catches, however: it’ll be produced in very small numbers – Mercedes is predicting an initial run of just a couple of hundred cars – and you won’t actually be able to buy it.

Like the Honda FCX Clarity, the F-Cell will be available for lease by a few select customers.

If you can find somewhere to refill your F-Cell with hydrogen, it should be an efficient thing to run: Mercedes says it will return the equivalent of 87mpg and a range of around 250 miles on the New European Design Cycle (NEDC), and – being a hydrogen fuel-cell car – and emit precisely 0g/km of CO2.

Performance, though, should be comparable to a B-Class powered by a 2.0-litre petrol engine: the 134bhp electric motor will hustle the F-Cell to 62mph in just under 11 seconds, with the full 214lb ft of torque available from idle.

But you’ll need to be able to fill the thing up. Mercedes acknowledges that a comprehensive network of hydrogen filling stations is necessary to make fuel cells commercially viable, and says it is working with governments to make this network a reality.

If you've got a few minutes to kill, watch Mr May in the Honda FCX Clarity: