The Oil Spill Commission previously stated the decision on centralisers appeared to highlight "a rush to completion" at the drilling site. But in a hearing last week, it also said that BP had not sacrificed safety to save money.

BP had not commented at the time of writing, but said in a Bloomberg in August that in order "to deflect attention away from its potential role in the well blowout, Halliburton has tried to focus the public's attention on the number of centralisers used by BP in the Macondo well". It insisted Halliburton had not deemed the cement job to be unsafe, and questioned the cement slurry mix.

Halliburton declined to comment. A spokesperson at Transocean, the rig owner, said: "Transocean does not - and did not in connection with the Deepwater Horizon - operate in preference of time or cost over safety." Procedures were "designed and directed by BP's expert personnel on the rig and onshore", the spokesperson said.

The slide was not used at a key hearing this month, but was accidentally posted to the OSC website, the . It had been intended for the meeting, but it was not signed off by the commissioners and so was pulled at the eleventh hour.

An OSC spokesperson told the newspaper: "We wish that the slide had been part of the presentation, and the information will be used, I predict, in the future, either in our remaining meeting or in the final report."