JAPANESE car-makers have led the way on environmentally friendly vehicles but they're about to take frugality to new levels and shift the pollution debate onto electricity providers.

At the opening of the Tokyo motor show yesterday Toyota, Japan's biggest car-maker, unveiled a model that sipped fuel at half the rate of its petrol-electric Prius. There are two catches: it has no doors and you can't buy one. Yet. The 1/X is a concept only but is a pointer to a shift in Toyota's view on "plug-in" hybrid cars that can be charged overnight on a home power point.

Car-makers' increasing dependence on electricity could produce a fundamental shift in the energy debate. At the Detroit motor show in January, the product planning boss of GM, Bob Lutz, told the Herald: "If people want an electric car, we can deliver it. Now go and get your electricity from a clean source."