It will travel four times as far as a Rolls-Royce Phantom on a single gallon of petrol. It emits so little carbon dioxide that it escapes both the London congestion charge and British road tax. On the debit side, it is somewhat gruff and noisy, and it vibrates a bit. It is called the Volkswagen Polo Bluemotion.

This is VW’s take on an environmentally friendly car that does not resort to the complexity and hidden CO2costs of hybrids or other alternative propulsion systems. Its arrival comes amid environmentalists’ challenges over the extra energy spent and CO2 generated in manufacturing two propulsion systems for hybrid cars.