Drivers in small rural and coastal towns are particularly suffering from high prices, the AA said.
It added that between mid November and mid December, the average UK price of petrol rose from 130.44p a litre to 131.17p, while diesel increased from 137.78p to 138.61p.
In Scotland, diesel was even more expensive, at 139.4p.
The AA said Government statistics for retail sales and fuel consumption show that, despite this autumn's 7p-a-litre crash in the petrol pump price, petrol sales failed to rebound.
Unlike the aftermath of previous fuel price spikes this year and last year, UK petrol sales in October fell by 26 million litres on the month before.
The AA said the October figure of 1.486 billion litres was only seven million litres more than the slump in March last year when average prices were heading towards the all-time record of 142.48p a litre, reached on April 16 2012. AA president Edmund King said: "High pump prices have taught the UK motorist how to save on fuel and the fear is that, although petrol prices are down more than 10p a litre compared to the record of 142.48p, drivers are now applying those savings to shoring up other parts of the family budget, such as rising gas and electricity bills.
"It doesn't help when hundreds of thousands of drivers in small rural and coastal towns with uncompetitive supermarkets are being charged 4p or 5p a litre more for the cheapest petrol than in neighbouring towns."