An "unusual piece of data" caused widespread flight disruption, an air traffic control (ATC) boss said, as airlines are under growing pressure over their treatment of passengers.Many UK holidaymakers are stranded overseas after around 2,000 flights were cancelled because of the issue.There is speculation the ATC failure was caused by a French airline submitting a flight plan to National Air Traffic Services (Nats) in the wrong format.Downing Street did not rule out that possibility, while Nats d

An "unusual piece of data" caused widespread flight disruption, an air traffic control (ATC) boss said, as airlines are under growing pressure over their treatment of passengers.Many UK holidaymakers are stranded overseas after around 2,000 flights were cancelled because of the issue.There is speculation the ATC failure was caused by a French airline submitting a flight plan to National Air Traffic Services (Nats) in the wrong format.Downing Street did not rule out that possibility, while Nats declined to comment on whether that was what happened.Flights to and from UK airports were restricted for several hours on Monday afternoon as the fault prevented flight plans from being processed automatically, meaning manual checks were required.