It looks like many was ill informed when you went out looking for a new/secondhand car, diesel is the best, you get more miles from the vehicle , its cheaper to tax (not all). and its good for the environment too.
Well you all have been fooled it seems.
A friend has always had diesel cars and he use to laugh at me in my toyota , i get more miles to the gallon and i pay less car tax then you he use to say.
I was in to minds whether to change the car to a diesel one, but i dont do the miles , plus i am happy with what i have.
It will not be long before you will be paying higher vehicle tax again plus maybe going into cities there may be some sort of city tax,