Fresh highs for crude oil prices are threatening to put beleaguered motorists under renewed pressure.

With the cost of New Yorktraded oil close to $60 a barrel, there were fears among motoring groups that the average price of a litre of unleaded petrol could break through April's record of 86.05p.

The AA Motoring Trust reported pump prices of 85.93p a litre this weekend, following a rise from 84.53p at the start of the month. It pointed out the impact of the high petrol price between mid-April and mid-May alone was likely to have taken £4.38 million a day away from high street spending.

The latest increase in the cost of US light crude came after ongoing supply worries were compounded by a threat to western consulates in Nigeria, which is Africa's largest oil producer and the fifth biggest source of US oil imports.

At one point the the cost of crude oil for July delivery reached $59.23 a barrel, a rise of 76 cents from Friday's close and the second straight day that oil has set intraday records. On London's International Petroleum Exchange, Brent leapt 77 cents to $58.53 a barrel.

While oil futures are more than 50 per cent higher than a year ago, they are still well below the inflation-adjusted high above $90 a barrel set in

1980. The Organisation of Petroleum Exporting Countries failed to lift the market last week when it agreed to raise its daily output quota to 28 million barrels a day because its members had already been unofficially exceeding that level.

Analysts have blamed the recent increase on speculative buying, ongoing supply fears and limited excess production and refining capacity.

Edmund King, executive director of the RAC Foundation, warned there was likely to be an inevitable knock-on impact on petrol prices.

He said: "We are likely to see more increases at the pumps as the oil price goes up. All we can hope for is that one of the chains breaks rank, as some of the supermarkets have done in the past."

Mr King added: "The difference between now and the fuel protests of 2000 is that motorists are aware that these increases are down to world prices rather than tax increases."