EU didn't mandate it, but they did lead the drive to more efficient engines which in turn led motor manufacturers down the diesel road. We were 'late adopters' of diesel in the UK compared with mainland Europe. It's relatively recently that Government have woken up to the serious health impacts of the diesel engines' tiny soot particles on human health (environmental scientists and groups have been going on about it for years). Our Government has been delaying and obfuscating in the face of the EU threatening us (and other countries) with massive fines for failing air quality targets which are in place to reduce the number of people dying. Here's an example of different approaches. When there's bad air quality in Paris, the Mayor bans cars and encourages people to use public transport, cycle and walk. When there's bad air quality in London, the Mayor tells people not to exercise outside but does nothing to stop people driving or encouraging them to use other means of transport.well thats a shit sandwich to chew on for all those that took up diesel as a greener option. i think EU actually mandated increased use as a way to reduce CO2 (because its more efficient than petrol)