for green-minded people who want to show the world that they are holier than thou. Brad Pitt, Cameron Diaz, Leonardo DiCaprio and Billy Joel were among the first American stars to turn up at awards ceremonies in a 'Pious', since when Toyota has sold almost half a million of them in America.

Toyota claims that the Prius will average 57.6mpg - and so it might if it were never driven outside of congested American cities, where it runs on its electric motor. In Britain, however, no long-term test of this car has achieved an average consumption that comes close to that figure, and one reliable test returned 38.1mpg. Such figures are no better than those of many conventional petrol-engined cars the same size as the Prius, and are far worse than all equivalent diesels.

The Toyota Prius, therefore, is truly about as green as Rantzen's backside.