Although Lexus's hybrid synergy drive has evolved, the principle remains the same: a battery powers an electric motor at low speeds for a range of nearly two miles and a petrol engine does the rest with the battery-powered electric motor helping out. When you're off the gas or braking, the system recharges the battery.
The power is channelled through a continuously variable automatic transmission that's green in itself, but which whines unusually when you ask for more power. It's not horrid, just something you'll need to get used to.
If you can live with the noise that a hard shove on the throttle induces, performance is really rather good there's plenty of mid-range power and the engine noise soon settles back to, well, silence.