Following the explosion and fire on the rig, the blow-out preventer on the sea bed should have automatically sealed the well, but it failed, resulting in the massive oil spill.

BP PLC Chief Executive Tony Hayward has come under mounting pressure over the spill, caused after a drilling rig BP was leasing, the Deepwater Horizon, caught fire and sank last month.

His insouciant handling of the oil spill in the Gulf is under fire from all sides.