The two people arrested over drone activity that brought London’s Gatwick airport to a standstill in recent days have been released without charge, leaving police to continue their search for those behind the incident.
Sussex police said a 47-year-old man and 54-year-old woman from Crawley, West Sussex, had been released without charge on Sunday morning. They had been arrested on Friday on suspicion of disrupting civil aviation in a way likely to endanger people or operations.
“Both people have fully co-operated with our inquiries and I am satisfied that they are no longer suspects in the drone incidents,” said Jason Tingley, Sussex Police detective chief superintendent.
Drone activity at the UK’s second-largest airport caused about 1,000 flights to be cancelled or diverted, disrupting the travel plans of about 140,000 passengers between Wednesday and Friday.
Flights were grounded on Wednesday evening and all day on Thursday following reports of drones operating over the airfield that prompted safety concerns because of the risk of collisions with passenger jets.
Flights were first restarted on Friday morning, 36 hours after Gatwick suspended them. They were suspended again briefly on Friday afternoon after reports of another drone sighting, before resuming in early evening because, the airport said, “the military measures we have in place at the airport have provided us with reassurance necessary that it is safe to reopen our airfield”.
Gatwick said on Sunday that the airport was fully up and running.
On Sunday evening Birmingham airport briefly suspended flights because of an “an air traffic control fault”. Disruption began at around 6pm and was cleared around two hours later. after the problem had been resolved.
Sussex Police said no further information could be provided in relation to the Gatwick investigation. On Friday, Steve Barry, assistant chief constable, said it was “an incredibly difficult offence to detect and arrest the suspect for”. He added that there were a “whole spectrum of possibilities, from high-end criminals to individuals trying to be malicious”.
Mr Barry said there was “no evidence” the drones that targeted Gatwick were state-sponsored.
Chris Grayling, the UK’s transport secretary, told the BBC that the attack was thought to have been carried out by “a small number of drones” operated by one person or a small number of people.
There had been “more than 40 sightings” over the airport between Wednesday night, when the airport first suspended flights, and Thursday night, but these were “the same small number of drones, seen many times”, he said.
Mr Grayling insisted the government had “put in place every measure we possibly can to ensure this can’t happen again. What’s happening on the ground is a mix of measures taken to give confidence that aircraft can be safe . . . some of those are military capabilities.”
He added: “The reality is that this technology, the ability to stop drones, is really only just emerging. We are going to have to learn from this what the existing technology can do, what else needs to be done.”
The Ministry of Defence began providing support to Sussex Police on Thursday. People briefed on the military’s involvement said the Royal Air Force had provided a tracking system that gave police and security staff early warning of drones.
The MoD would not confirm what RAF equipment was being used, but it is thought to have been part of a system deployed in May to provide security for the wedding of Prince Harry and Meghan Markle at Windsor castle.
Earlier versions of the tracking and surveillance kit were also deployed at the 2013 G8 summit in Northern Ireland and at a 2014 Nato gathering in Wales.
Barry Jenkins, a former army air-defence commander and now director of counter-drone strategy at Drone Major Group, a consultancy, said detecting and deterring drones posed a significant challenge.
“Drones are a small radar cross-section target and therefore a radar will have trouble picking them up,” he said.
Reporting by Myles McCormick, Conor Sullivan, David Bond, Sylvia Pfeifer, Naomi Rovnick and Robert Wright