In the first testimony from a high-ranking BP executive, Mr McKay stressed that all those involved in the Deepwater Horizon disaster should take some of the blame.

BBC: BP: Gulf of Mexico oil spill 'shared responsibility'

Despite declines in production volumes, high oil prices are helping BP generate a strong cash flow.

FORBES: Banged-Up BP Still Worth $55

While the calibre of civil servants was "generally very high", the former BP boss said there was a lack of staff with commercial skills or expertise in handling major projects.

BBC: Civil service pay: 57 fewer top earners than a year ago