Can someone explain that if we get over $2 to the pound and oil price is high why petrol prices are going up?

Our price is $.99/litre.

There are 3.785 litres in an American gallon, so we pay--assuming exchange is equal--$3.75 if we bought gas in the US. In Britain, we'd pay $4.50 because there are 4.546 litres in an imperial gallon.