Petrol prices have fallen but drivers are still being short-changed, according to the AA.
Average petrol prices have gone down from 138.95p a litre in mid October to 135.08p now, with diesel dropping from 143.74p a litre to 141.89p.
But the fall in wholesale petrol prices across Europe should have knocked UK pump prices down by 10p to 11p a litre, the AA said.
Tax on fuel will rise by 3p in January
The AA added that despite the threat of an Office of Fair Trading (OFT) investigation of the road fuel market, "conditions that led to drivers and businesses being short-changed at the pump in the spring have happened again".
The AA said that UK drivers were also suffering again from "price postcode lottery" where motorists in one area can be charged as much as 5p a litre more than drivers a few miles away.
On average, the cheapest petrol at the moment is in Yorkshire and Humberside (134.3p a litre) and the most expensive is in south-east England at 135.7p.
Yorkshire and Humberside also has the cheapest diesel (141.0p) with Northern Ireland the most expensive (142.6p).
Motorists received another blow earlier this week when Labour's Commons motion to have the planned January 3p-a-litre fuel duty rise deferred was defeated.
However there is speculation that Chancellor George Osborne will announce a postponement of the rise in his autumn statement next month.
AA president Edmund King said today: "It should beggar belief that, after the trauma of high fuel prices in the spring, the same thing should happen again six months later. But we are talking about the fuel industry.
"Recent political focus has been on the January fuel duty increase, either ignoring or unaware that duty's ugly sister, unrestrained wholesale prices, has been running rampant in the fuel market."
He went on: "The Government momentarily had a grip of this monster when the previous transport secretary (Justine Greening) called in the industry to agree wholesale price transparency. This initiative stalled when the OFT called for information on road fuel pricing - to which the industry has responded by pumping up wholesale prices and then not passing on cost savings in a timely fashion.
"The average UK domestic energy bill is £1,252, but the cost of fuel for the average car consuming 1,200 litres a year is over £1,500. This week the Government said it was going to tackle high gas and electricity bills, yet lets drivers and businesses down by not reacting swiftly to runaway wholesale and pump prices."