Mercedes calls it a ‘multi-drive platform’, and the F800 Style is built to take both hydrogen fuel-cell and plug-in hybrid powertrains, with the former offering a range of 375 miles and the latter allowing for 19 zero-emissions miles. Because Mercedes has managed to shrink the size of its F-Cell (fuel cell) componentry, the F800 can squeeze the fuel cell or plug-in hybrid powertrains into the engine compartment and (says Mercedes) the gaps within the chassis. And there’s still room inside for five.

The plug-in version of the F800 Style has a next-generation, direct-injection 299bhp 3.5-litre V6 petrol engine, mated to an 80kW hybrid module that’s integrated into the seven-speed gearbox. There's also a lithium-ion battery with over 10kWh of storage capacity, and the F800 can reach 75mph in electric mode – it manages 155mph with petrol power – and return 68g/km.

The all-electric version features a 100kW motor that develops 214lb ft and is powered by a hydrogen full cell and lithium-ion batteries. The technology is a development of the system found in the B-class F-Cell, though adapted for the F800’s rear-drive layout.