Equipment used to measure and sell petrol is controlled by law and all pumps have to be made to an approved pattern, tested and approved before they can be used.
Fuel pumps are tested by Trading Standards Officers for accuracy and to make sure they are within the law. We also keep a record of any complaints made. In addition many petrol stations employ engineers to test their equipment for accuracy to control the stocks and can use authorised officers to certify new equipment or equipment in use after a repair.
Fuel pumps are sealed to prevent adjustment and fraud. They must operate within tight guidelines.
The equipment is designed to measure the volume of fuel sold and then multiply this volume by the price per litre, to calculate the price to pay. In this calculation the price will be rounded to the nearest penny.
The fuel is measured by volume and this is used to decide the price to pay. When the price of fuel increases, the amount of fuel becomes less. As the volume sold increases, so the price goes up.
The law says any error on selling petrol can be no more than 2p.
If you have any concerns about the operation of a pump please notify the petrol station manager. If you are not happy with the explanation given please contact Citizens Advice consumer service.