A 100-ton concrete-and-steel box was being lowered towards the undersea blown-out US well today in a pioneering attempt to stop most of the crude oil pumping out into the Gulf of Mexico.

The worst US oil spill in decades spread into precious shoreline habitat along the Gulf Coast today as documents emerged showing British Petroleum downplayed the possibility of a catastrophic accident at the offshore rig that exploded.

BP downplayed the possibility of a catastrophic accident at an offshore oil rig that exploded and caused the worst spill in decades along America’s Gulf Coast, it emerged today.