More than 2,000 flights have been cancelled due to the air traffic control outage
A technical failure of the UK's air traffic control system that has caused widespread flight chaos was avoidable, according to the Transport Secretary.
Heidi Alexander told the Commons she had ordered an independent investigation by the aviation watchdog into the system operated by Nats, which went down for four hours on Tuesday.
More than 2,000 flights have been cancelled as disruption continued for a second day with passengers stuggling to fly out of and into the UK.
After meeting with the boss of Nats, Martin Rolfe, Alexander said a cyberattack could be ruled out, but she added: "I do not believe this issue was unavoidable."