Petrol prices: Some rural areas like 'fuel deserts'
Filling a vehicle at the petrol pump can be an expensive business, so it will be a surprise to many that a price war is going on.
Supermarkets use low prices to draw customers in. In order to compete, many independent petrol stations are cutting prices too.
Philip Hampsheir investigates how motorists can find the cheapest place to get a full tank.