(Alliance News) - Air passengers have been warned they face delays after UK air traffic control systems were hit by a technical fault.
The National Air Traffic Services, the country's leading provider of air traffic control services, said it has applied traffic flow restrictions on Monday to maintain safety following a technical issue.
The PA news agency understands passengers boarding flights both to and from the UK have been told of the fault.
In a statement, NATS said: "We are currently experiencing a technical issue and have applied traffic flow restrictions to maintain safety.
"Engineers are working to find and fix the fault. We apologise for any inconvenience this may cause."
Meanwhile, airline Loganair warned customers they may experience delays as a "network-wide failure" has affected air-traffic control systems on Monday morning.
The Glasgow-based airline posted on X, formerly Twitter: "There has been a network-wide failure of UK air traffic control computer systems this morning.
"Although we are hopeful of being able to operate most intra-Scotland flights on the basis of local co-ordination and with a minimum of disruption, north-south and international flights maybe subject to delays.
"If you are flying with us today, please check our website for the latest information about your flight before setting off for the airport."
At Stansted, Ryanair passengers told PA they had been told to wait at their gate until further notice.
British Airways said in a statement: "We are working closely with NATS to understand the impact of a technical issue that is affecting UK airspace and will keep our customers up to date with the latest information."
Michele Robson, who used to work in air traffic control, said that it was "unusual" for failures to last this long.
She told BBC Radio 4's World at One programme: "There was a flight planning system failure this morning which affected both centres in the UK."
Speaking from Jersey Airport while waiting to fly to London, she said: "Now they have enough data for four hours for controllers to work normally. After that point, they have to go manual which means that they work at a much slower rate so they can handle far less aircraft.
"So it looks like there's been what they would call a zero rate put on, where it means that no aircraft can take off inbound to the UK or probably outbound. It would generally be them trying to land things that were already in the air.
"So at the moment, we're just sitting here with no definite takeoff time."
She said failures normally "only last a couple of hours".
"It's unusual for it to be off for this amount of time. So nobody really knows at this point how long it's going to take."
BBC presenter Gabby Logan said she had been caught up by the issue.
She posted on X: "On a plane on the runway at Budapest airport. After almost 3 weeks away from home I am hours from hugging my family.
"And have just been told UK airspace is shut. We could be here for 12 hours. So we sit on the plane and wait."
By Gwyn Wright, PA
source: PA
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