CONTROLLERS at Swanwick's air traffic control centre had to guide flights manually this morning after the second computer failure in a computer system in a month.

Aircraft were grounded and flights were delayed after the glitch at the West Drayton centre, near Heathrow, which is connected to the new centre at Swanwick.

The failure meant that flight data normally produced electronically had to be prepared by hand after the computer failure at 6.05am.

The flight data system was out of use for 20 minutes and the air traffic control system was fully operational afterwards.

National Air Traffic Services spokesman John Freeman said: "The problem at West Drayton had a knock-on effect at Swanwick.

"It affects the flight strip information controllers have to prepare giving information about destinations and routes.

"Although the computer system is fine now we have to catch up on a backlog of flights."

Mr Freeman added that a full investigation is under way to identify what caused the com-puter breakdown.

Flights were grounded at Stansted, Birmingham and Manchester airports and flights delayed at Heathrow, Gatwick and Southampton airports.

At Southampton incoming flights from the Channel Islands were delayed and morning departures to Paris, Amsterdam, Brussels, Dublin, Edinburgh and Glasgow were an hour late taking off.

An airport spokesman said: "There have been delays but we are hoping to get things back to normal as soon as possible."

These incidents are a further setback for the newly-privatised National Air Traffic Services (Nats) which has had to receive a £30m bail-out from the government after run-ning into financial difficulties following the events of September 11.

A group of seven airlines has taken a 46 per cent stake in Nats. Yesterday, one of these partner airlines - low-cost carrier easyJet - said it was considering writing off its investment.