The oil refineries were built years ago when petrol was far more popular than diesel. Most refineries are therefore set up to produce far more petrol than diesel. As diesel became more popular production struggled to keep up with the demand and like all things with limited supply the price went up. Add to that and greedy government and a couple of wars and you can see why the price is so high. Petrol & diesel are still too near the £5.00 per gallon mark for my liking.
