National Air Traffic Services (NATS) says there is no evidence to suggest the "technical issue", now resolved, was cyber-related.

Britain’s transport chief has summoned the head of the country’s air traffic control operator to explain the problem that grounded and diverted dozens of flights.

LONDON (Reuters) -A radar-related technical issue in Britain's air traffic control system disrupted flights for over four hours at major airports in London and elsewhere on Wednesday, though the issue was later resolved and departures were resuming.