You might think that with petrol in the US now costing more than $4 a gallon – $1 more than a year ago – it would be a great time to be selling the stuff. So why is ExxonMobil choosing now to dispose of its 2,200 company-owned service stations?

The reason is: $4 petrol. When approaching a service station, the first thing a driver sees is an oil company logo above a petrol price that, these days, goes ever upwards – not exactly a marketing executive’s dream. It is all very well trying to explain that high petrol prices are set much further up the supply chain – distribution and marketing account for only about 6 per cent of the price in the US. But consumers care little for such nuances.