Once the object of ridicule and focus of outrage after the 2010 oil spill in the Gulf of Mexico, BP former chief executive Tony Hayward made a cameo Wednesday at the trial over the disaster, briefly showing up on a videotape in what may be his only appearance in the courtroom.

Hayward, who famously said "I'd like my life back" at the height of the spill, isn't expected to take the witness stand in the high-stakes trial to determine how much more BP and its partners should pay for the spill.

While Hayward testified before Congress and gave a videotaped deposition for this trial, his role may be limited here by his lack of direct knowledge of the drilling operations on the Deepwater Horizon.

Still, attorneys for the U.S. government and Gulf Coast residents and businesses showed a 20-minute snippet of his deposition, projecting the video on a large white screen in the courtroom. The attorneys have said the London-based company bears most of the blame for the spill and they accused BP of putting profits ahead of safety by cutting corners on a project that was over budget and behind schedule.

"I believe that the role of leaders is very important in shaping the culture of an organization," Hayward said in the videotape.

He also said cost-cutting measures in the years before the 2010 spill did not have an effect on drilling operations, comments that differed from excerpts of a videotaped deposition from Kevin Lacy, who served as BP's senior vice-president for drilling operations in the Gulf before resigning several months before the spill.

'I was never given a directive to cut corners.' —Kevin Lacy, former BP Sr. VP

Lacy said BP slashed between $250 million and $300 million US from its Gulf drilling budget from 2008 to 2009 while at the same time its production rose by more than 50 per cent.

"I was never given a directive to cut corners or deliver something not safely, but there was tremendous pressure on costs," Lacy said.

U.S. District Judge Carl Barbier is presiding over the trial designed to identify the causes of BP's Macondo well blowout and assign percentages of fault to the companies involved. If BP is found guilty of gross negligence, it could be on the hook for nearly $18 billion.

The rig explosion killed 11 oil rig workers and the busted well dumped an estimated 652 million litres of oil into the Gulf.

Barbier listened to the videotape that featured a lawyer asking Hayward about a speech he gave just five days before the blowout.

Hayward spoke about the company's "drive to increase efficiency and reduce costs."

"The context was I'd spent time talking about safe, reliable operations before I talked about any of this," Hayward said.

Hayward also drew a distinction between reducing "corporate overhead" and cutting "corporate operating costs."

While the busted well spewed oil into the Gulf, Hayward was photographed at a yacht race and also accused of directing his employees to downplay the disaster to keep stock prices afloat.

Hayward personally devastated

Hayward told Congress he was personally devastated by the spill and that it never should have happened. He stepped down as CEO and later left the company.

Rig owner Transocean Ltd. and cement contractor Halliburton also are defendants and their lawyers have tried to minimize their roles in the disaster. BP attorneys have said the drilling was a team effort and that all of the companies share responsibility for the disaster.

Meanwhile, a witness for the federal government testified BP withheld critical information from industry regulators and continued drilling despite clear signs of trouble before the blowout.

Alan Huffman, a well design expert and geophysicist who has worked for Conoco and Exxon, said BP continued drilling in dangerous deep water conditions without keeping the Minerals Management Service fully informed.

Huffman said his review of internal BP documents and MMS records showed the oil giant engaged in a "consistent pattern of misreporting" to the federal agency and gave it a "very false impression" of what was happening on the drilling project.

"And this happened on multiple occasions ... not just on one or two," said Huffman, the second expert witness at a trial that started Monday and, barring a settlement, could last several months.

BP pleaded guilty in January to 14 criminal counts, including 11 felony counts of manslaughter, and agreed to pay $4 billion in criminal penalties to resolve a Justice Department probe. Transocean pleaded guilty earlier this month to one misdemeanour count of violating the Clean Water Act and agreed to pay $400 million in criminal penalties.