Busy airport suspends all flights, causing severe disruptions during one of the heaviest travel times of the year.

London’s Gatwick Airport, the second-busiest in the United Kingdom, has shut down while officials urgently investigated reports that two drones were flying above the airfield.

The airport suspended all flights late on Wednesday, causing severe disruptions just days before Christmas, one of the heaviest travel times of the year.

An increase in near collisions by unmanned aircraft and commercial jets has fuelled safety concerns in the aviation industry in recent years. Flying a drone within 1km of an airport or airfield boundary was made illegal in Britain at the end of July.

Police and aviation authorities were still investigating early on Thursday as incoming flights were diverted to other locations in the UK and nearby countries.

Passengers complained on Twitter that their flights had landed at London Heathrow, Manchester, Birmingham and other cities. Other flights were sent to France and the Netherlands.

Fully appreciate that this isn’t your fault, but is there any news on diverted flights? We have no one in arrivals telling us what is happening. It’s pretty poor really. There are young children waiting here #gatwickairport #drones — Danuta Kean #MaskWearer #notAnInformer (@Danoosha) December 19, 2018

One traveller whose flight was diverted tweeted that passengers were not being told when they could continue to their destination.

Gatwick advised travellers via Twitter to check flights scheduled for Thursday before heading to the airport. It also advised anyone planning to pick up arriving passengers to check first.

Any problem at Gatwick causes a ripple effect throughout Britain and continental Europe, particularly during a holiday period when the air traffic control system is under strain.

A busy airport 43km south of Britain’s capital, London, Gatwick hosts a number of short- and long-haul flights and serves as a major hub for the budget carrier easyJet.

The airport normally operates throughout the night but the number of flights is restricted because of noise limitations. According to its website, it usually handles 18 to 20 flights overnight during the winter months.

In a statement, Gatwick apologised for the inconvenience but said it had to put safety first.

There have been occasional reports of drones nearly hitting commercial airliners in the London area in recent years.

Strong sales of small consumer drones have led to repeated warnings about a possible threat to scheduled flights.