BMW - which famously once boasted that it would be the first carmaker to put a hydrogen-powered vehicle into production - has taken another step towards making good on its promise.

The company says its hydrogen-powered 7 Series, dubbed the Hydrogen 7, has successfully completed development. The BMW 7 Series Hydrogen 7 Saloon is powered by a 260 horsepower, 12-cylinder engine and accelerates from 0-100 km/h (62mph) in 9.5 seconds.

Top speed is limited electronically to 143mph.

And as long as full supply of hydrogen is not guaranteed, the dual-mode power unit featured in the BMW Hydrogen 7 switches over quickly and conveniently to conventional premium petrol.