UK petrol prices could soon rise to levels not seen since the autumn of 2000, when widespread protests caused fuel shortages.
Fuel prices have been pushed higher by rising crude prices, which last week hit their highest level in 13 years.
And there could be worse to come, Ray Holloway, head of the Petrol Retailers Association, said.
"We'll see [prices] going up again as soon as this week," Mr Holloway said.
Petrol and diesel prices tend to follow oil prices, and crude oil has become ever more expensive in recent weeks.
The cartel of oil producing countries, Opec, does not accept blame for the high crude oil prices - even though it decided to cut output at a meeting in Algiers last month.
"I am convinced there are two reasons for such a high price: the reduced quantity of petrol in America, and speculators who are convinced there is going to be a lack of crude," said Saudi Oil Minister Ali al-Naimi in an interview with the Italian newspaper Il Sole 24 Ore.
Current oil prices are so high, that some Opec members are worried about the market's stability.
To ease the supply squeeze, the organisation is reportedly considering postponing its planned 1 April supply cut.
"Opec may consider delaying the cut until June when we meet next week," an Opec delegate told Reuters.
"The idea is there, but there is no formal proposal as yet."
The news saw crude prices fall back from recent highs, with May Brent crude slipping 56 cents to $32.70 a barrel in early trading on Monday, while the US benchmark crude Nymex slipped back below $38 per barrel for April delivery, though oil is still not cheap.