Some of the sightings of drones near Gatwick Airport may have involved the police’s own craft, a senior officer has said.

Police received 115 reports of sightings in the area last week, including 93 which have been confirmed as coming from “credible witnesses”.

None of the sightings of police drones caused the shutdown of the airport which led to widespread travel disruption, Sussex Police said.

Officers have not yet found the drone used to disrupt around 1,000 flights last week and do not know its model, but two drones found by police near the airport have been ruled out of involvement.

Sussex Police Chief Constable Giles York’s said he was “really sorry” for a couple who were held for 36 hours before being cleared of responsibility for the disruption.

Mr York insisted he is “absolutely certain” a drone was flying near runways at Gatwick during the three-day period from December 19-21 when the airport was repeatedly forced to close.

But he acknowledged there may have been some “confusion” caused by his force launching its own drones in the hunt for the rogue craft.

Speaking to BBC Radio 4’s Today programme, Mr York confirmed military technology had been installed at Gatwick following last week’s incident, “dramatically” improving security at the airport. But he could not rule out future disruption of the same kind.

Mr York said a Sussex officer who suggested last week that police were not sure whether there was a drone flying at Gatwick at all was simply trying to explain the investigative approach taken by the force.

“I am absolutely certain that there was a drone flying throughout the period that the airport was closed,” he said.

Police received 115 reports of sightings in the area, including 93 which have been confirmed as coming from “credible people"..

But Mr York told Today: “Of course, we will have launched our own Sussex Police drones at the time with a view to investigate, with a view to engage, with a view to survey the area looking for the drone, so there could be some level of confusion there.”

Describing the police investigation as “incredibly thorough”, he said: “I don’t think we have found the drone responsible for this at this time.

“I think the fact that we have found two drones so far as a result of this does show the extent of the search that has been carried out. I am led to believe that we are able to rule those drones out of this investigation at this time.”

The officer also said he felt “really sorry” for Paul Gait and Elaine Kirk, from Crawley, West Sussex, who were detained in the wake of the disruption, but said the grounds for their arrest were “well founded”.

The couple have said they felt “violated” by their lengthy questioning, the search of their home and the way in which their identities became public.

Mr York defended the decision to hold Mr Gait for an extended period, despite his employer saying he was at work during the drone flights.

“I’m really sorry for what he has experienced and the feeling of violation around it,” said the chief constable.

“I am really sorry for what he went through, but the reason why we held him was so that we could dispel everything in the first instance. What might have been worse as an experience for him would have been to be released under investigation still."

Thousands of pre-Christmas journeys were disrupted by flight cancellations at Gatwick Credit: PA