Remember fuel cells? About ten years ago they were all the rage. And you could see why: the technology required to react hydrogen with oxygen in a fuel cell was known and the result – the creation of energy with water as the only emission - represented something close to an environmental nirvana.

Better still even back then they offered a range that a battery powered electric vehicle could not even dream about plus, and here’s the killer, the ability to replenish its hydrogen supply in much the same 3-4 minutes as it takes to fill a tank with petrol or diesel.

Yet it all came to nothing. The fuel cell fuss died down and while no manufacturer admitted canning a fuel cell programme, so too did they start pushing other environmental technologies rather harder: hybrids, plug-ins, range-extenders, battery electric vehicles, any really so long as it wasn’t a fuel cell. The reason? A simple lack of infrastructure: the best fuel cell car in the world is useless if you’ve nowhere to fill it up. There was much talk (remember Senator Schwarzenegger’s much mooted hydrogen highway up the California coastline) but next to no action.

But now, at least according to Dr Dieter Zetsche, chairman of Daimler AG and head of Mercedes-Benz cars that may be about to change. Fuel cells, he says are back on the agenda.

"It is no secret that the launch of electric vehicles has been more troublesome than some at first thought," he told me at the Beijing motorshow, "and this is why people are now looking more seriously at fuel cell cars again."

It seems beyond doubt that all major car manufacturers will have to have at least a proportion of zero emission cars in their portfolio to cope with any zero emissions city centre legislation that might be forthcoming and fuel cells might play a part in that.

But what of the ongoing issue of infrastructure? "For this you need Government support, you cannot do it on its own. But while it is true that Governments expressed interest and then lost interest, I’d say we were now past the tipping point and their interest is rising again."

There is nothing concrete Dr Zetsche will point to but as he says, "you can sit back and watch others take up the challenge or you can be a pioneer and take it up yourself. At Mercedes-Benz, we prefer to be pioneers."