Two of the world’s largest oil companies have unveiled plans to jointly develop a multibillion dollar pipeline to move natural gas from Alaska’s energy-rich North Slope to US markets.

Oil prices steadied today despite continued uncertainty over the scale of disruption caused by BP’s shutdown of a key Alaskan oilfield.

BP says the corrosion discovered at its huge Alaskan oil field is so severe it could shut down America’s single biggest source of domestic crude for months and drive world fuel prices even higher.

Two of BP’s new double-hull tankers that carry Alaska crude oil have developed mysterious cracks in their rudders, the company said.