A power distribution failure caused some IT systems at British Airways' data centre to shut down on Saturday, disrupting flights and causing delays at Heathrow.

Shortly after 6am, a power cut disconnected access to the airline's departure control and cargo systems.

The connection was restored by 9am, but the initial disruption caused delays later into the day. Eleven short-haul flights from Heathrow's Terminal One were cancelled.

A BA spokesman confirmed that computers at other Heathrow terminals and UK airports were not widely affected, and that the failure did not disrupt global systems, as some reports suggested.

"We're currently trying to establish precisely what caused the problem," he said.

The BA.com website was not affected by the power failure nor were any other systems. The company said that all services had returned to normal by Sunday.

The outage was the latest trouble to hit BA in a difficult year. The airline suffered extensive flight cancellations and delays in July after check-in staff at Heathrow went on an impromptu strike to protest about the introduction of electronic swipe cards.

The Iraq conflict and the Sars outbreak hit its long-haul business hard.

Rod Eddington, BA's chief executive, said this week that a recovery in the airline industry was still some way off. The market appears to have bottomed out, but there is little evidence of any upturn, he explained.