@EDDIE: you'd be surprised what a modern petrol engine can do mileage-wise. Up to a year ago, we had two cars - same make and model - one with petrol engine, one turbo-diesel. The petrol averaged 45 and the diesel 62 mpg. We sold both and bought a new petrol-engined car (stop-start engine, regenerative braking etc) which is averaging 65mpg...and no VED.
You have to take many things into account before choosing...no only annual mileage but type of traffic and,of course, higher initial price of diesel vehicles and (usually) dearer servicing.
Incidentally, I never had any problems with either the petrol or diesel cars we owned and would certainly have another diesel....if the annual mileage and driving conditions warranted it.