With a tax rate on profits of 33 per cent in a typical year, that would cut BP’s tax bill by about $10bn.
BP paid $8.4bn in worldwide tax on profits last year, down from $12.6bn in 2008 because of the fall in oil and gas prices.
Of that 2009 payment, £930m went to the British government: about as much as is paid by the UK’s entire transport and communications industries.
The company does not give a full geographic breakdown of its taxes, but its payments to the US are likely to have been of a similar size.
Irene Himona, an analyst at Exane BNP Paribas, estimated that before the Deepwater Horizon accident, BP was set to pay about $37.5bn in tax during 2010-13, but the costs of the disaster would cut that to $27bn.