BP faced fresh controversy today after shareholders filed a lawsuit against senior executives following the partial shutdown of its oil field in Alaska.
The investors say they have been let down by failures to repair the pipe in the Prudhoe Bay oilfield, which has been partially closed after a leak.
The closure has significantly cut the field's 400,000 barrels per day output.
Highly respected BP chief executive Lord Browne of Madingley and a number of other senior executives now face legal action after shareholders alleged the company knew about the pipeline corrosion for years.
The shareholders claim BP took no substantial steps to properly monitor and repair the pipes, which ferry oil straight into the 800-mile trans-Alaska pipeline.
Oil from Prudhoe Bay makes up about 8% of US oil supply.
The lawsuit is the latest problem to blight BP's Alaskan operations after a criminal investigation was launched into a major leak that spilled 267,000 gallons of oil across the North slope of Prudhoe Bay in March.
