reconnaissance

Riley's role in the Dalston attack had been to carry out reconnaissance of the restaurant, scout for potential targets and to drive the gunman away in a stolen car.

Riley admitted conducting reconnaissance, spotting targets and picking up the gunman, but claimed he believed it was a "smash-and-grab" robbery.

Experts say these could be used for a variety of tasks from reconnaissance and sweeping for mines, to hunting down enemy soldiers.

As if to underscore the point, the Pentagon ordered 4,000 Marines and sailors to the waters of Latin America and the Caribbean, alongside Navy destroyers, reconnaissance aircraft and a nuclear-powered missile cruiser.

Remotely-piloted drones are already in use with HM Coastguard and the Royal Navy, performing search and reconnaissance roles, but the unmanned police helicopter will be the first flying over residential areas.