FLIGHTS into the UK were suspended for two hours today after staff at a Hampshire air traffic control centre were forced to abandon their computer system.

Controllers at the National Air Traffic Services complex in Swanwick had to guide aircraft manually after computer problems hit the centre at 6am.

All departures from airports across the UK were grounded until 8am although some incoming flights - both domestic and international - were able to land.

Reports suggested that there had been a computer problem at NATS' West Drayton site, near Heathrow, which processes information for Swanwick.

It meant operators at Swanwick had to return to the old, slower system of guiding aircraft into land.

The £623m Swanwick centre has been dogged by problems. It opened in January 2002, more than six years behind schedule and more than £200m over budget.

It handles around two million flights a year and employs 800 people.

Southampton Airport was hit by the problems. The first departure was scheduled for 6.30am to Malaga, Spain. It did not take off until 7.21am.

By 8.20am flights had also taken off for Paris, Amsterdam and Man-chester.

Inbound planes from Leeds, Manchester and Belfast were delayed. Flights from the Channel Islands arrived with minimum delays.

About 350 passengers flying out of Southampton were affected.

An airport spokesman said: "We are trying to get things back to normal. People will need to expect some delays as we get people moving."

Passengers Chris and Catrina Simmonds, from Boston, said: "We are trying to get back to Paris. The plane is here. It was to fly out at 9.10am. It's now a case of waiting to find out if it takes off on time."

A Hampshire businessman, who did not want to be named, said: "I have an important meeting to get to in Manchester.

"I was due to fly out at 8.30am. I don't even know if my plane is here. I have meetings arranged from 10.30am onwards so it will cause major problems."

NATS, which provides air traffic control services in the UK, said it was looking into reports of a "computer system problem".

Adrian Yalland, spokesman for NATS, said its computer system had crashed just after 6am and had affected airports across the UK.

But he said the system was now "fully operational" and they were working to clear the backlog of delayed flights.

Mr Yalland added: "Our computer system is now fully operational and safety being our primary concern we are now working to make sure those aircraft in the air and in need of landing should be able to do so to clear the delays.

"The fault is thought to lie with the data processing system. We think it is to do with the flow of data. The reasons why planes were grounded was because we couldn't let them into the air which would add more complications.

"We wanted to ensure the safety of flights in the air, over-flights of the UK, that is."

He said he did not know how many flights had been affected by the computer crash or how long the delays would be.

"The system is not going to go down again," Mr Yalland added.

A BA spokesman said there was no security risk to passengers and the system would be run manually by controllers in the centre.

But the size of the problem was likely to cause "severe delays throughout the day", she added.