BBC News with Ian Purdon.

The US Interior Secretary Ken Salazar has sharply criticised the oil company BP for its handling of the huge oil leak in the Gulf of Mexico. Speaking after a visit to BP's American headquarters in Houston, Mr Salazar said he was angry and frustrated that BP has missed deadline after deadline to stem the flow of oil. He said the disaster represented a crucial challenge for the company.

“I have no question that BP is throwing everything at the problem to try to resolve it because this is an existential crisis for one of the world's largest companies. Do I have confidence that they know exactly what they are doing? No, not completely. “