LONDON -- British Airways GMB union has blamed the airline's 2016 decision of outsourcing IT jobs to India as the reason behind cancelling all Saturday flights from London's two biggest airports: Heathrow and Gatwick.

The GMB union said the airline's decision to outsource hundreds of IT jobs to India last year was behind the problems, the Guardian reported. The GMB union said BA laid off hundreds of IT staff last year and outsourced the work to India and blamed cost cutting for the travel chaos.

"This could have all been avoided," said Mick Rix, national officer for aviation at the GMB union. According to the GMB website, the union had on February on February 29, 2016 warned against BA outsourcing IT jobs.

British Airways has cancelled all flights from Heathow and Gatwick on Saturday due to a major IT failure causing severe disruption to its global operations that is expected to run into Sunday. The airline said its terminals at Heathrow and Gatwick became "extremely congested" due to the computer problems.

Initially the major IT failure was being speculated as that BA's IT systems had been hacked as recently WannaCry ransomware attack affected 150 countries. "We believe the root cause was a power-supply issue and we have no evidence of any cyber attack," Chief executive Alex Cruz said.

The computer crash affected BA's booking system, baggage handling, mobile phone apps and check-in desks, leaving passengers facing long queues and confusion in airports or delays while planes were held on runways. More than 1,000 flights were affected. At Heathrow alone, BA had 406 flights scheduled to depart after 9am and a further 71 at Gatwick, according to flightstats.com on Saturday.