Heathrow and Gatwick affected by IT failure closing London airspace - UPDATED

Another IT failure causes flight disruption as London airspace is closed due to an IT glitch

Airspace around London has been closed for the afternoon following another IT failure at the Swanwick air traffic control centre. The shutdown will affect planes flying from and to London's major airports, including Heathrow, Gatwick, Luton and Stansted.

The airspace will be closed until at least 7pm - possibly later - which will affect hundreds of flights at two of the world's busiest airports. The failure occurred at about 3.10pm today.

In a statement, the National Air Traffic Service (NATS) said: "NATS can confirm that a technical problem has been reported at Swanwick air traffic control centre. We apologise for any delays and our incident response team has been mobilised. Every possible action is being taken to assist in resolving the situation and to confirm the details."

However, NATS did not release precise details about the IT failure.

It is not the first time in recent years that NATS has suffered an embarrassing IT problem. In December 2013, passengers were left stranded due to an issue with "very complex and sophisticated" software.

In July 2013, a major IT glitch stopped flights into and out of London Heathrow and Gatwick, but London airspace wasn't closed as a result.

And back in 2005, the organisation had another failure that led to flight delays, which it attributed to flaws in flight data software.

UPDATE: According to NATS, the system is back up-and-running as of 4.30pm this afternoon. "Following a technical failure at Swanwick, the system has been restored and we are in the process of returning to normal operations," claimed the organisation in a statement.

While NATS is remaining tight-lipped about the cause of this latest glitch, reports suggest that it was caused by a power failure to a key system, and the subsequent failure of diesel back-up generators.