Passengers are facing widespread flight disruption after a computer failure at the UK’s air traffic control centre, the BBC reports.
Nats said it was in the process of returning to normal operations after a “technical problem” at its Swanwick control centre caused delays and grounded some flights.
Problems were reported around the UK.
The government said the scale of the disruption was “unacceptable” and said it had asked for a “full explanation” of what had gone wrong.
This included delays at Heathrow and Gatwick, where departing flights were grounded for a time. Other UK airports reported knock-on effects.
It comes a year after a telephone glitch at the Hampshire control room caused huge disruption – one of a number of technical hitches to hit the part-privatised Nation Air Traffic Services (Nats) since the centre opened in 2002.