We're on the far side of 150mph and the car hasn't changed gear yet. What's more, if I now back off the throttle, a small flow diagram tells me that I'm saving the planet by recharging the nickel-metal hydride battery underneath the rear seats. Who needs to hug trees?

This, the Lexus GS 450h, is the first rear-wheel- drive hybrid to reach the market and the second hybrid from Lexus following the launch of the RX 400h last year. It's powered by a 292bhp 3.5-litre V6 and a permanent-magnet electric motor producing 197bhp (up 20 per cent on the RX's). When they overlap in operation, peak power is 340bhp. The killer figure though is the 203lb ft produced by the electric motor from standstill, which helps the GS hit 62mph in under 6sec and backs up its claim to offer a genuine alternative to a powerful V8 saloon.

The GS 450h also has the most complicated transmission in the world. Forget DSG, SMG and Ferrari's F1 system; the Lexus's Power Split Device has 'a central sun gear, an outer ring gear and intermediary planetary pinion gears which engage the central and outer gears'. Not only does this complete solar system of cogs allow the electric motor to run independently of, or in conjunction with the V6, but it also cleverly eliminates the need for a starter motor. Then there's the E-CVT, which ensures the apparently seamless progress up to 150mph. I say apparently because of course there's also the two-stage motor speed reduction gear (low gear for high-torque acceleration and high gear for high-speed cruising with better fuel efficiency) that changes over imperceptibly at about 56mph. Confused? You should see the diagrams...

It all amounts to 35.8mpg on the combined cycle and similar CO2 emissions to an economy-tuned four-cylinder diesel. You don't have to pay the congestion charge either.
Impressive as the technology is, however, the GS is still monumentally dull and the 450h doesn't help by sounding like a Flymo, the E-CVT maintaining an unwavering bluebottle buzz all the way to your desired speed. In town it's fun cruising silently past pensioners and making them check their hearing aids but it's hardly the thrill of driving.

It's hoped that hybrid will do for Lexus what quattro did for Audi, but whilst the technology and foresight are certainly to be applauded, I can't see one turning up in the WRC anytime soon.