Depending on which garage forecourt you go to, you will see regular diesel and premium diesel available. Premium diesel contains additional chemicals that are designed to help clean your engine to preserve its life and increase efficiency, although there is no independent evidence to back this up.

The shelf life of both kinds of diesel are broadly the same - it begins to degrade after 28 days and by six months it can start to break up, so we would not recommend using diesel that has been stored for this long.