LONDON • The worldwide IT meltdown was caused by a power surge at about 9.30am on Saturday that had a "catastrophic effect" on British Airways' communication hardware, "which eventually affected all the messaging across our systems", BA chief executive Alex Cruz said.

He told the BBC that this affected "all the operating of our systems - baggage, operations, power processing".

Backup systems that should have kicked in also failed, he said, adding that there was no evidence of a cyber attack and "there has been no corruption or any compromise of any customer data".

Mr Cruz said BA is conducting an exhaustive investigation and will share the results.

"We will make sure that nothing like this ever happens in British Airways again."

Mr Cruz also said he would not resign over the incident, rebuffing claims by the GMB union that the disruption "could have all been avoided" if BA had not cut hundreds of IT jobs in Britain and transferred the work to India.

"I can confirm that all the parties involved around this particular event have not been involved in any type of outsourcing in any foreign country. They have all been local issues around a local data centre, which have been managed and fixed by local resources," he said.

Tens of thousands of passengers were left stranded following the failure on Saturday, which shut down all of the carrier's check-in and operational systems, and affected call centres and its website.

BA's outage came on a busy weekend in Britain, when Monday was a public holiday and many schoolchildren were beginning a week's holiday.

Passengers were asked to contact BA to locate their luggage after many were forced to leave Heathrow airport without claiming their bags.

Mr Cruz said that 75,000 passengers were affected by the failure.

AGENCE FRANCE PRESSE