Delays are expected for passengers at airports around London after the national air control computer system stopped working this morning.

The national air traffic control (nats) computer system crashed about 6am and was not restored until 7am, causing delays and knock-on effects.

It was reported the error occurred during maintenance work on the computer system.

Air traffic controllers were working to prioritise aircraft in the air, leaving all departing flights grounded.

British Airways flights from Heathrow this morning were delayed by up to an hour and twenty minutes.

Airlines advised passengers to check as normal but expect possible delays.