Sussex Police assistant chief constable Steve Barry said the last confirmed sighting of a drone was at 10pm last night.

"The key is we've now got some options around the airport from a police perspective and that puts us in a much better position to respond to drone sightings," he told BBC Breakfast.

"There are a range of options, some of them very sophisticated and some of them less sophisticated, but it has as I say put us in a much better position to respond to any of those drone sightings."

He went on: "The last few days has been unprecedented nationally I would say, I mean we have had minor incursions previously at Gatwick and we have responded to those really effectively.

"But like I say, this scenario that we're dealing with has been unprecedented so in terms of getting the level of options available to respond to it, to mitigate it, to detect it and respond to it, that has taken us some time, but I'm really confident now that we've got everything we possibly could have here at Gatwick."

Asked if the disruption was part of an environmental protest, he said: "Well it's certainly something that we would consider. Yes, I would agree that's a possibility.

"At this stage we're certainly not linking it to terrorism, but obviously we keep an open mind and I can understand the perception.

"It is, as I say, an unprecedented level of disruption to national infrastructure to the passengers themselves. It's really really significant. But in terms of the motivation as I say you know we're exploring lines of enquiry around that but at this stage we're not saying that it is terrorist related."