Cancelled flights are displayed on the departures board at Heathrow Airport. AP
Passengers wait at Heathrow Airport. The UK's air traffic control systems have grounded thousands of flights on one of the busiest travel days of the year. PA
Planes line up at Manchester Airport. EPA
Passengers check the boards at Stansted Airport, north of London. AFP
Passengers wait at Belfast International Airport, Ireland. AP
People wait near packed check-in desks at Gatwick Airport. Getty Images
Passengers queue in a departure lounge at Heathrow Airport in London. EPA
People wait near check-in desks at Gatwick Airport. Getty Images
Passengers look at departure boards at Belfast International Airport. PA
Passengers check the departures board at Heathrow Airport. AP
Cancelled flights are displayed on the departures board at Heathrow Airport. AP
Passengers wait at Heathrow Airport. The UK's air traffic control systems have grounded thousands of flights on one of the busiest travel days of the year. PA
Planes line up at Manchester Airport. EPA
Passengers check the boards at Stansted Airport, north of London. AFP
Passengers wait at Belfast International Airport, Ireland. AP
People wait near packed check-in desks at Gatwick Airport. Getty Images
Passengers queue in a departure lounge at Heathrow Airport in London. EPA
People wait near check-in desks at Gatwick Airport. Getty Images
Passengers look at departure boards at Belfast International Airport. PA
Passengers check the departures board at Heathrow Airport. AP
Cancelled flights are displayed on the departures board at Heathrow Airport. AP
UK air-traffic control hit by 'network-wide failure' - in pictures