§ Mr. GillTo ask the Secretary of State for Transport whether he will make a statement about the potential benefits to the environment of encouraging the greater use of diesel engines in motor cars.
§ Mr. Chope[holding answer 10 July 1991]: Compared with their catalyst petrol-engined counterparts, diesel cars are generally worse emitters of NOx and particulates, but better on carbon monoxide and CO2. Given that diesel cars usually enjoy a 20 to 30 per cent. advantage in fuel economy, and that duty on diesel fuel is slightly less than on petrol, there is already an implicit encouragement towards diesels, particularly for high-mileage users.