IT glitch affected more than 1,000 flights over weekend meaning people missed holidays, lost luggage or were stranded on aircraft.

British Airways could face a bill of at least £100m in compensation, additional customer care and lost business resulting from an IT meltdown that affected more than 1,000 flights over the weekend.

All the airline's flights from Heathrow and Gatwick were grounded on Saturday. Services resumed on Sunday but cancellations and delays delays persisted with about 200 BA flights in and out of Heathrow cancelled on Sunday, according to Guardian calculations. There were no cancellations at Gatwick but some passengers experienced delays.

The glitch is believed to have been caused by a power supply issue and there is no evidence of a cyber-attack, the airline said.

In a video posted on YouTube, Alex Cruz, chief executive of BA, said that all the IT systems were not yet restored. "Many of our IT systems are back up today. All my British Airways colleagues on the ground and in the air are pulling out all the stops to get our operation back up to normal as quickly as we possibly can, we're not there yet."

Left stranded by the BA meltdown? Here's how to seek compensation

"I know this has been a horrible time for customers. Some have missed holidays, some have been stranded on aircraft, some separated from bags and some stuck in long queues while they have waited for information. On behalf of everyone at BA I want to apologise for the fact you've had to go through these very trying experiences," said Cruz.