This afternoon, Gatwick Airport tweeted: "Flights to and from Gatwick and other London airports are subject to delays and cancellations, due to a technical issue with Air Traffic Control.
"We advise anyone travelling today to check the latest information on their flight with their airline."
At 3pm, NATS - the air traffic control service - released a statement that said: "Following the technical problem at Swanwick air traffic control centre this morning, we have now fixed the issue sufficiently to safely increase traffic flow rates and will see an improving picture through the rest of the day. We apologise for the inconvenience caused.
"However, the weather is continuing to cause significant unrelated disruption across the country and more widely across Europe, which has further complicated today’s operation."
The knock-on impact of the technical problems means many flights are still being delayed or cancelled.
Gatwick Airport advised passengers to check with their airline for updates.