It lists a range of potential targets including foreign embassies, nuclear power stations, a G7 summit or the prime minister’s car. “The UK government, police, military and security services will need to introduce countermeasures to reduce or mitigate the risk of commercially available drones being used for attack,” it reads.

Recommended countermeasures include licensing drones, laser systems to protect targets, radio-frequency jammers, and clear guidance for the police and the army to shoot down hostile drones.

The study analysed more than 200 drones available to buy on the high street or on the internet and warns many are capable of being converted to deliver an explosive payload.

It also warns that the dangerous capabilities of drones are increasing and yet they are already being used by terrorists and activists. “The technology of remote-control warfare is impossible to control,” the report says.