FLIGHT problems across the south last week were caused by an unprecedented systems failure.
Airports were forced to delay and cancel flights after a technical problem occurred at Swanwick-based National Air Traffic Services (Nats).
Problems started Friday afternoon and affected Heathrow, Southampton and other airports across the UK.
Nats revealed that the problem occurred when one of their systems failed while switching between on and off.
A statement said: ‘In normal operations the number of workstations in use versus in standby fluctuates with the demands of the traffic being controlled.
‘In this instance a transition between the two states caused a failure in the system which has not been seen before.
‘The failure meant that the controllers were unable to access all of the data regarding individual flight plans.’
Over the weekend, Heathrow had 38 flights cancelled before 9.30am Saturday and many flights Friday evening were delayed for several hours.