AIR traffic bosses in Hampshire have apologised tonight after a computer glitch caused chaos for hundreds of thousands of travellers.

Journeys were thrown into chaos after problems at the National Air Traffic Services control base in Swanwick, near Fareham, saw hundreds of flights cancelled or delayed, sparking the worst disruption since the volcano ash crisis three years ago.

Last night they apologised for the huge disruption that had particular ramifications in southern England - blaming a very complex system combined with the need to keep people safe in the skies.

In Southampton, a total of 34 flights were affected at the airport by the problems with the telephone systems, although fortunately, none were cancelled.

Of the 25 flights into the airport on Saturday, nine were directly affected with delays by the chaos and five were indirectly delayed.

While of the 24 outbound flights, eight were delayed as a direct result of the problems and 11 were delayed as a result of delays elsewhere.

A spokesperson from Southampton Airport confirmed that some flights suffered delays of up to two hours but that they had caught up by about 4pm, operating as normal on Sunday.

Across the country thousands of people endured hours of frustration as flights were affected, including the major airports of Heathrow, Stansted and Gatwick.

The problem was resolved at about 7.30pm on Saturday, more than 12 hours after first being reported.

It was feared there could be knock-on effects but other than a handful of cancellations at Heathrow, there were no further problems. The issue arose when Nats' night-time operating system, which combines sectors of airspace for when it is less busy, did not properly switch over to the daytime system, causing a communication problem with the centre's internal telephones. They stressed that safety was not at risk at any time.

Heathrow was the worst affected, with 228 cancellations, representing 15 per cent of its usual daily total of 1,300 flights going in and out of the airport. In a statement Nats apologised for the disruption, saying: “The reduction in capacity has had a disproportionate effect on southern England because it is extremely complex and busy airspace and we sincerely regret inconvenience to our airline customers and their passengers.

“To be clear, this is a very complex and sophisticated system with more than a million lines of software.

“This is not simply internal telephones, it is the system that controllers use to speak to other ATC agencies both in the UK and Europe and is the biggest system of its kind in Europe.

“This has been a major challenge for our engineering team and for the manufacturer, who has worked closely with us to ensure this complex problem was resolved as quickly as possible while maintaining a safe service.”