PinkPaisley - the reason that this offence has a special name is that it is not really theft, although it is sometimes referred to as a form of theft. The reason is that at the time you take the petrol, you have the company's consent to do so. When you get to the till, you can hardly give it back, so ownership has to pass to you at an earlier stage. The same thing happens in a restaurant, where the proprietor would be unimpressed to have the consumed food returned. You have a debt, but it was criminalised a few years ago.