Campaigners say they are "bitterly disappointed" that the competition watchdog has ruled out a full investigation into the fuel market after concluding high prices are the fault of taxes and the cost of crude oil.
The Office of Fair Trading (OFT) said competition in the sector was "working well" and there was "very limited evidence" that pump prices rise quickly when the wholesale price goes up but fall more slowly when it drops.
Furious campaigners, who had called on the OFT to announce a full investigation into the sector, said drivers would feel let down by the findings.
FairFuelUK spokesman Quentin Willson said: "UK consumers will be bitterly disappointed. The nation will feel let down. Quite frankly, I'm shocked. The OFT investigated in 1998 and now have done so again. Every motorist and business in Britain instinctively knows that something's not right. The Americans and the Germans are holding inquiries - why aren't we?
"The OFT appears to have failed to address the key issues of why diesel is more expensive than unleaded in the UK when this is not the case in Europe, why falls in the oil price take so long to be reflected at the pump and why there are such variations in price, often from the same branded forecourts, within the same area.
"They did not address the whistleblower evidence of potential rigging of the oil commodity market. Where is the fairness in all of this?"
RAC technical director David Bizley said: "We're extremely disappointed to hear the OFT will not be launching a full-scale review of petrol and diesel pricing in the UK. We have campaigned long and hard for greater price transparency and will continue to do so until this is recognised as a serious issue."
The OFT's report found that the UK had some of the cheapest pre-tax road fuel prices in Europe, noting that in the 10 years to 2012 pump prices increased from 76 pence per litre (ppl) to 136ppl for petrol, and from 78ppl to 142ppl for diesel, caused largely by an increase of nearly 24ppl in tax and duty and 33ppl in the cost of crude oil.
Its analysis of the relationship between retail and wholesale prices at both a national and local market level, as well as the relationship between crude oil prices and wholesale prices at a national level, turned up "very limited evidence" to support claims of so-called rocket and feather pricing.
However the investigation did identify a lack of pricing information on motorways as a concern and the watchdog said it would not rule out taking action in some local markets if there was "persuasive evidence of anti-competitive behaviour".