Parking his sports car alongside other executives' Audis and BMWs in businessman Richard Branson's grand estate in Oxfordshire, Jeremy Leggett - the last person you would describe as a petrolhead - had just made history.
The chief executive of Solar Century and former Greenpeace activist had become the first person in the UK to test drive the revolutionary Tesla sports car, powered entirely by electricity.
He drove from London one evening for the business awards event at Branson's home with Rosie Boycott, a former newspaper editor.
The first time he overtook a car on the motorway, Leggett asked his companion to tell him if he was driving too fast. 'No you're not, dear,' Boycott replied, 'just make sure you get us there in one piece.'
With the car doing 0-60mph in just four seconds, you can't blame her nervousness. About 650 Tesla roadsters will be made this year, at a cost of $100,000 each. The car, which can travel 362km before it needs to be recharged, is challenging the accepted wisdom that electric cars are no match for their dirtier petrol - or diesel-powered rivals.
The attractions of finding an alternative to the internal combustion engine are growing. Environmental regulations are also increasingly discriminating against conventional cars.
In Europe, for example, MEPs (members of the European parliament) are hammering out the details of a new law that if approved will force car-makers to cut the carbon emissions of their new models by about a fifth from 2012 or face massive fines. So faced with swingeing regulations, are the days of the conventional engine over?
Car-makers are working on myriad new technologies to reduce the reliance on petrol and diesel and offer competing claims as to why their chosen technology is superior to rivals'.
Broadly speaking, these can be split into three categories: electric vehicles, hybrids that combine electric power with another source, and those powered by hydrogen fuel cells.
Only the first two categories are available in car showrooms now, and in tiny numbers. According to the car manufacturers' trade body the SMMT, last year just 397 pure electric cars, such as the G-Wiz, were sold in the UK, less than 0.02 per cent of the total.
Hybrids, like Toyota's Prius, notched up about 16,000 sales or 0.6 per cent. Analysts estimate that as the technology becomes cheaper, hybrids could make up about 14 per cent of total new car sales by 2012.
The Prius hybrid teams a petrol engine with an electric battery that powers the car at low speeds. At high speeds and with fast acceleration, the Prius's petrol engine kicks in.
As a result, the Toyota has far lower emissions than other mid-range cars. But critics point out that smaller conventional cars have lower emissions than the Prius, which needs to be larger to accommodate the engine's extra weight and so consumes more fuel.
The big car-makers are working on 'next-generation' hybrids. GM is developing the Chevrolet Volt, run entirely on electricity but with an internal combustion engine that recharges the battery. It hopes to start large-scale production within five years. Cost is a big issue however: charity WWF estimates that a battery system for these 'plug- in' hybrids costs about $10,000 more than one for a conventional dual- fuel system.
Further away, despite the initial success of the G-Wiz car and the emergence of the Tesla, is the mass roll-out of pure electric cars. Fossil fuels give a car more range and higher speeds than even the most advanced batteries, which are heavier and need to be recharged more regularly than a tank needs to be refilled with petrol.
Electric cars also need a network of charging points. The vast majority of electric cars are sold in London, as it is the only city in the UK to have installed charging bays on the street and in car parks.
Steve Hartridge, managing director of GoinGreen, which distributes the G-Wiz in the UK, admits: 'The roll-out of the G-Wiz in the UK has to be gradual.'
Paul Newton, analyst from Global Insight, cautions: "There is no doubt that we are approaching a tipping point, but it is very early days."