BP is facing fines from American regulators over the problems with its corroded and leaky pipeline that forced it to shut down the Prudhoe Bay oil field in Alaska and dry up as much as 8 per cent of US daily oil supplies.

Leading energy analysts have predicted that US regulators will act against BP, particularly after details of its poor maintenance track record emerged earlier this week.

BP is already facing criminal charges over a previous leak at the pipeline earlier this year.

The likelihood of fines, which analysts suggested would be less than $100 million, comes as the state of Alaska seeks possible redress against BP for daily tax and royalty losses of $6.4 million a day related to the pipeline closure. Alaska generates 89 per cent of its income from Prudhoe Bay.

Bill Hedges, the integrity management team leader at BP Exploration Alaska, has admitted that before its most recent clean-up operation, the oil group had not comprehensively cleaned transit pipelines at Prudhoe Bay since about 1992, a period of almost 15 years.

"Well, clearly we need to review that because with hindsight that is clearly a gap in our programme," Mr Hedges said in a conference call with the media earlier this week.

Analysts said it was "standard practice" to routinely clean up transit pipes, in order to remove dirt and debris and spot corrosion at an early stage.

Adrian Jackson, energy analyst at Investec Asset Management, said: "BP did have the reputation, like Exxon, for being among the most operationally efficient of the super-majors, but I think this is beginning to get stretched.

"The Prudhoe Bay issue has been rumbling for a while, but has suddenly now sprung to prominence. BP has a growing list of problems, with the fire at the Texas refinery and delays in recent deep water developments. At the moment they are probably just about being given the benefit of the doubt by shareholders."

He said the implications for BP's revenues are "relatively small and there probably won't be any legal actions from shareholders; but there are likely to be fines". Government agencies and safety bodies such as FERC, who give permits to operate and monitor safety, might get involved, he said.

FERC said yesterday that it was not currently involved with the problems at Prudhoe Bay and said issues of pipeline safety were a matter for the Department of Transportation.

BP did not return calls seeking comment yesterday and no-one was immediately available to comment this morning.

Although BP executives acknowledged that the group did not have a regular programme of "pigging", or cleaning the pipes, they did point out that there were regular ultrasonic surveys to determine the condition of the lines.

It is also the latest in a growing list of setbacks for BP's American operations, led by new boss Bob Malone.

Last month BP said it would be spending a total of $7 billion on improving procedures at the embattled subsidiary, which in the past 18 months has suffered fatal fires at its Texas refinery, a wave of hurricane damage and allegations of trading manipulation in the propane market.

BP embarked on a major shutdown of Prudhoe Bay last weekend, which could "shut in" 400,000 barrels of oil a day, equivalent to 8 per cent to daily oil supplies to America. It said it had discovered "unexpectedly severe" rust and a leak in a pipe.

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