The joint BP-US government response team said there were doubts that the oil had drifted all the way from the spill.

BBC: Gulf oil spill reaches Texas as tar balls wash ashore

Facing challenges in other parts of the world, and having sold its Russian joint venture TNK-BP, it sees the US as central to its plans for future growth.

CNN: BP claims it now leads the way on safety

We then worked -- a group of us worked with a group from BP, including the chairman, Mr. Hayward and others to make that happen.

WHITEHOUSE: Press Briefing on BP Oil Spill

There is also a chance that BP will end up not paying dividends this year and it is almost certain that the amount BP is having to pay out for the clean-up in the US will eventually affect the dividend.

BBC: Why is BP important to the UK economy?

In a 30-minute phone call, the US president said he recognised BP was a multinational company and he had no interest in undermining its value.

BBC: BP criticism not about nationality, says Obama

The two BP site leaders at the well - Robert Kaluza and Donald Vidrine - have been indicted on manslaughter charges in the US for their alleged role in misinterpreting the test results.

BBC: BP: Scope of oil disaster internal probe 'had limitations'

For the US government it's all the resources they're spending on the trial - particularly if BP is not found grossly negligent.

BBC: BP oil spill trial told it 'put profits over safety'