UK motorists have been receiving an unexpected bonus of free extra fuel, according to testing undertaken by the AA.
The motoring organisation conducted testing on petrol pumps after members were concerned that they were not getting the full amount of fuel they were paying for.
However, the AA found that motorists were actually receiving 4.4 per cent more fuel on average than they were paying for because of inaccurate counters at petrol stations.
The research found that all nozzles tested at petrol stations gave out at least the recorded amount with some dispensing more.
The AA said Trading Standards officers had found 11 errors out of the 216 petrol stations tested in Derby and four inaccurate readings out of 38 sites tested in Cumbria.
This meant that on some occasions motorists were receiving up to 6p a litre extra in fuel for free.
The AA said the inaccuracies were down to the age of some pumps. The UK has a mix of old and new pumps and the AA said that in many ways UK motorists have been playing a game of “lucky dip” when filling their vehicles with fuel and that record high fuel prices has produced desperation amongst some poorer drivers.
AA president Edmund King said: "Some drivers have been benefiting from a lucky dip at the pumps, getting more fuel than they pay for.
"Inevitably, some motorists are watching their gauges like hawks and complaining to Trading Standards."
Mr King added that fuel prices have risen by 17.5 pence in the last two years and that this has forced drivers to pay more attention to fuel consumption and costs.
The UK will be affected by an EU ruling that will force petrol stations to meet the Measuring Instruments Directive by the end of October 2016.
UK fuel prices have reached a record high this year and coupled with falling disposable income has forced the government to bow to pressure and postponed a planned August 3p a litre increase in fuel duty until January 2013.