According to NATS, the UK-based air traffic control service: “We have identified and remedied the technical issue affecting our flight planning system this morning. We are now working closely with airlines and airports to manage the flights affected as efficiently as possible. Our engineers will be carefully monitoring the system’s performance as we return to normal operations.

“The flight planning issue affected the system’s ability to automatically process flight plans, meaning that flight plans had to be processed manually which cannot be done at the same volume, hence the requirement for traffic flow restrictions. Our priority is always to ensure that every flight in the UK remains safe and we are sincerely sorry for the disruption this is causing. Please contact your airline for information on how this may affect your flight”.

In Portugal, there have been reports of passengers at Faro Airport being warned of delays of up to five hours.

According to CNN Portugal, a source from ANA - Aeroportos de Portugal admitted that restrictions in UK airspace may have "some impact" on flights to and from the UK at all national airports, and there may be delays or cancellations. ANA advises passengers departing or arriving at Portuguese airports to contact the airlines to find out more information about the status of scheduled flights.

While the issue has been resolved the knock-on effects of the problem has meant that many UK airports foresee continued issues on one of the busiest days of the year for travel.

According to a report by Sky News, Manchester Airport have said: "As a result of the nationwide technical problem experienced by NATS earlier today, there continues to be flight disruption, including delays and cancellations." Meanwhile, Heathrow Airport issued the following statement: "The technical issue which limited UK air traffic earlier today has been fixed by NATS. However, schedules will remain significantly disrupted for the rest of the day. We ask passengers to only travel to the airport if their flight is confirmed as still operating.