November reflected four months of successive reductions in the average price of petrol.
A litre of unleaded fell by half a pence to 125.93p in the month – representing four months of failing prices.
In addition, a litre of diesel also fell by a similar amount from 130.27p to 129.83p during November. It has fallen for three out of the last four months, having increased slightly during September.
It means that the cost of filling up an average 55-litre family car with unleaded is now £1.82 cheaper than it was in early August, while filling up the same sized tank with diesel in £1.21 less.
In November, both fuels fell by 25p resulting in a £69.26 fill for petrol and £71.41 for diesel.
Simon Williams, RAC fuel spokesman, said: “Due to savings in the wholesale price of both fuels Asda led a round of supermarket fuel cuts in late November which the other three major retailers followed.
“Despite this knocking off about a penny and half from the average price of fuel charged at the four big supermarkets, the UK average only reduced very slightly. This implies that other retailers haven’t followed the supermarkets lead and are not passing on savings in the wholesale price. This is bad news for drivers as it means they are losing out every time they fill up.”
Since the start of August, the average price of petrol across the UK has fallen by 3.31p a litre, and diesel a penny less at 2.21p falling from 132.04p.
At the end of November Asda was the retailer with the cheapest petrol at 119.70p – 1.77p lower than Tesco. It was also the cheapest retailer of diesel, too.