Latest estimates indicated that the oil’s flow could exceed 40,000 barrels a day – some 1.68 million gallons.

Experts accused BP of making a “fatal miscalculation” in failing to realise the extent of the leak earlier on, saying that inaccurate calculations had prevented them from getting to grips with the problem.

The news threatens to further destabilise BP’s share price, which has dived in response to Barack Obama’s “aggressive” rhetoric against the company.

BP’s chairman Carl-Henric Svanberg has been called to the White House for an emergency meeting next week, as the transatlantic row sparked by the spill continues to escalate.