Pressure is mounting on drivers and car manufacturers to produce more environmentally friendly cars. The government has tightened the screw on company car drivers by lowering the CO2 bandings, which will raise employees’ tax bills, and linked free fuel for employees to emissions instead of the car’s engine size.

Additionally, road tax has been lowered to £55 (from a maximum £160) for a new band of ultra-efficient vehicles, though only one car, the Honda Insight, currently qualifies.

Michelle Kay, the managing director of a stress consultancy, is delighted. She spent £11,000 on a second-hand Honda Insight purely because of its environmental credentials. Kay, 38, who lives in Chiswick, west London, uses the hybrid petrol/electric car for her daily commute into Harley Street in the city centre.

“I bought it for a variety of reasons,” she said. “I’m interested in environmental issues and as I spend a lot of time in my car travelling around London I didn’t want to think I was pumping out all sorts of noxious fumes.

Also, I’m asthmatic and poor air quality is one of the contributors to that. And I wanted something that looked good. The Insight fulfils all those criteria.

“My job primarily involves looking at the work/life balance and stress issues, and commuting is one of the biggest stresses we have. I think if more people drove cars like this the air would be cleaner and life would be a lot more pleasant. If Honda can produce a car like this that is environmentally sound but also looks good, why can’t other manufacturers?” Sensing this changing mood among many drivers, manufacturers are now working hard to produce vehicles that not only emit fewer harmful pollutants and also to use more ecologically sound materials in their construction.

An increasing amount of time is spent building green machines that are constructed from the things we throw away on a daily basis; cars that can be almost completely recycled at the end of their lives; that are less polluting; and in one case even give the environment a helping hand.

If you believe that a truly ecologically sound motor vehicle doesn’t exist, Volvo has got news for you with a car that instead of just minimising the damage it does to the atmosphere actually helps to clean it up, according to the Swedish manufacturer’s boffins. Called VAAC, for Volvo ambient air cleaner, the system employs roof-mounted solar cells that power the car’s ventilation fan even when it’s parked.

Air is taken into the Volvo and harmful hydrocarbons and nitrogen oxides are filtered out so that when the air exits it’s cleaner than when it went in.

The man in charge of the project, Jan Karlsson, explained: “This system makes the car it’s mounted on even cleaner than an electric vehicle because it is a less-than-zero-emissions vehicle. If you take the gases from the tailpipe and subtract the pollutants in the VAAC filter you get a minus figure. We need to test it thoroughly before we put it into production but we hope to introduce it on cars for sale in eight to 10 years.”

Volvo is currently on its own with this innovation but other manufacturers aren’t sitting on their hands. For the past four years Volkswagen has been pursuing the route that not using fuel in the first place is better than cleaning up the results of burning it. To this end it built the world’s first one-litre car. Nothing revolutionary about small engines, you might think, but that figure is actually the amount of fuel the car uses to cover 100km. And it equates to an astonishing 282mpg.

The car looks like a fighter-plane cockpit on wheels and uses a highly sophisticated 300cc one cylinder aluminium engine coupled to a tiny magnesium gearbox and installed in a lightweight carbon fibre chassis. But however fantastic that sounds, its roots are in something a lot more prosaic: VW’s bottom of the range Lupo. A spokesman said: “Much of the advanced technology employed in the one-litre concept such as the use of lightweight materials like aluminium and magnesium and low resistance tyres was pioneered in a very economical version of the Lupo that was only sold on the Continent.”

Other manufacturers like Honda, with its Insight, and Toyota with the new Prius, are pursuing a different tack to fuel saving by mating petrol engines with electric motors. When the driver needs a power surge the battery unit helps, and the engine charges the battery when it is not being used.