Britain is at risk of terrorist attacks from drones, a leading designer has warned.
Dr Stephen Prior said that Isis had already used drones in Iraq and Syria and was surprised terrorists had not tried to do the same in Britain.
Drones can weigh as little as 500g and fly up to 100mph and the GPS tracking system can be turned off, which makes spotting them difficult.
Dr Prior said eagles had been trained to take out a drone and an RF transmitter gun could disable the electrics.
He told the Cheltenham Science Festival: “I personally don’t design these systems to drop bombs on people’s heads.
“However, Isis has been one of the first terrorist groups to go and buy a very cheap drone, convert it and use it to very devastating effect in Iraq and Syria.
“They can go on a course to learn about it and nine months later they can build their own one and fly it around the world.
“I am surprised, frankly, that more drones have not been used to do bad things already. I think it is only a matter of time before somebody tries something.”
Dr Prior, who is a qualified drone pilot and lecturer in unmanned air vehicles at the University of Southampton, said stealth made drones difficult to stop but that did not mean the technology should not be developed because of the good it can do.
“The smaller the item the harder it is to see, the smaller the signature, the smaller the RF (radio frequency) footprint,” he said.
“As we have seen on the news recently a car is a devastating terrorist weapon, so is a lorry. We built it for a purpose which was not terrorist activity but if you want to create mayhem the tools are there.
“If people want to do bad with something they will. Whether that is a knife they can buy in a shop for a couple of quid which is a very devastating weapon in someone’s hands causing mayhem on the streets.
“It almost impossible to defeat entirely and all you can do is have the surveillance tools to try and observe those people.
“There is no magic cure. Even the ones that are regulated and controlled in the sense of broadcasting their position, the first thing the terrorist can do is disable all of that.
“Unless you play by the rules you are not going to be able to deal with that situation.”
Dr Prior said that counter-drone technology was a developing field.
“Eagles have been trained to go and capture a small drone and literally pull it out of the sky and crash it into the ground,” he said.
“You can also use a very powerful RF transmitter gun to overwhelm the electronics in the drone.
“In Japan they have built a drone with a massive net which can capture the second drone while it is flying and then drag it to safety.”