The board of British Airways board is to demand an independent inquiry into the catastrophic power failure that left 75,000 passengers stranded over the bank holiday weekend.The airline is facing mounting questions over the mysterious “power surge” blamed for the chaos, which energy providers deny happened.BA chief executive Alex Cruz could be headed for a stand-off with senior board members, furious at the hammering the company’s reputation has taken and the ongoing chaos amid a lack of credible explanation.A full schedule did not resume for three days following the crisis last Saturday and many passengers are still waiting to be reunited with their luggage. The airline has been bombarded with requests for refunds and compensation. Willie Walsh, chief executive of International Airlines Group, BA’s parent company, said the supply went down on Saturday morning but that the problem was compounded by an “uncontrolled” reboot of the system, which then knocked out the entire IT infrastructure.The sudden return of power led to the loss of flight, baggage and customer communication information. BA’s uninterruptible power supply is supposed to use multiple power sources, including a standby generator, to maintain a constant supply to BA’s two main IT centres near Heathrow.A spokesman for National Grid said it had “no system issues on Saturday morning” and energy provider SSE, which runs the network in west London, said its systems were also “operating as normal” on Saturday.BA said: “We are undertaking an exhaustive investigation to find out the exact circumstances and most importantly ensure that this can never happen again.”But it declined to comment on boardroom plans for an independent inquiry. People sleep next to their luggage at Heathrow Terminal 5Credit:REUTERS/Neil Hall Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. The board is expected to demand an inquiry led by third-party investigators to establish what went wrong and why contingency plans failed to kick in.A source in the company told the BBC: “It would be impossible to pretend that it was great. We need to figure out how, and why, decisions on how to deal with it were taken.”BA was accused of greed after the GMB union suggested the chaos could have been prevented if the airline had not cut “hundreds of dedicated and loyal” IT staff and contracted the work to India last year. Mr Cruz insisted the outsourcing of jobs was not to blame for the “catastrophic” power failure.But the cause of the initial power outage and the subsequent surge remains enshrouded in mystery.