That would be too logical for the government

You could have a Range Rover sport diesel and do 5000 miles a year and put out the same ammount of co2 as a pugeot 208 thats doing 10,000miles a year. Yet one will cost you £400 and the other £1200+ a year.

I can only think that this new taxatrion is to try and convince people to think about electric cars. Even though some of those come with tax as well now.