Transocean slams BP's 'self-serving' Gulf of Mexico disaster report

Instead the report found: 'A sequence of failures involving a number of different parties led to the explosion and fire which killed 11 people and caused widespread pollution in the Gulf of Mexico earlier this year.'

BP shares retreated from earlier highs after the statements from Transocean and Halliburton but closed 5.3p higher at 412p, boosted by news this morning that credit ratings agency Fitch has upgraded its rating on BP to 'A' from 'BBB.' 

The agency said it has assumed BP will not found to be 'grossly negligent' by investigating authorities and has also assumed fines under the US Clean Water Act will be shared proportionately between BP and partners Anadarko and Mitsui.

The rating agency said the upgrade reflects the fact that there is little chance of further leaks and the 'substantial progress that BP has made to date in building up liquidity to address potential financial payments.'