Oil is a messy industry, in pretty much every conceivable way. There’s no such thing as clean oil, or an environmentally friendly oil company, but there are degrees of responsibility. Likewise with business ethics. The oil companies have been involved in some very murky business in the past, and some really do have blood on their hands. So, which is the best one to buy your petrol from? Here are the top five oil companies, and a few notes on their record.