Police drones could be used for car chases, tracking hidden suspects, monitoring riots or protests or traffic violations - but UK airspace is so crowded complex restrictions would need to be reworked before they could be used, a military expert has told The Huffington Post UK.
Huw Williams, unmanned systems editor for Jane's Defence Weekly, the authoritative military journal, told HuffPost UK that police drones would be cheaper in money and manpower, but could currently not be used in UK airspace.
On Monday, Police minister Damian Green backed the use of controversial unmanned drones to patrol the UK's skies, to monitor criminal activity and provide air support, saying they should be treated like "any other piece of police kit."
Police officers in Liverpool use a remote control drone fitted with a TV camera to help combat potential anti-social behaviour
Williams said: "You can't just send unmanned aerial vehicles (UAVs) into civil airspace. In places like Afghanistan, for example, airspace is controlled by the military, so the UAVs can be used, but there would need to be restrictions lifted before they could be used by police."
He described the drones which might be used by police as "the size of a hobby aircraft, with cameras onboard, although obviously much more sophisticated technology."
"They could be used for anything you currently use a police helicopter for, so to follow a car chase, or to find a suspect who is hiding or for search and rescue missions.
"The cameras they carry can be very sophisticated, they can lock onto a car and follow it, without having someone constantly monitoring the pictures. They can then be transmitted back to police HQ.
"They could certainly be used to monitor riots or protests, or even traffic, although there's plenty of cameras doing that already."
He added: "There's very little I can envisage them being used for that police helicopters do not already do, but they are cheaper to use.
"It would be great to use them, it would save a lot of money and manpower, and it's extremely interesting technology.
"But we already have a very crowded airspace, with civil and military airspace. It would take a good few years for restrictions to be worked out."
Chief Constable Alex Marshall, who heads the National Police Air Service, has recommended the use of drones, but added that the "public need to find it acceptable and it needs to be within the law."
Chris Cole, who runs drone monitoring site Drone Wars UK, told The Huffington Post UK regulation which hampers the use of police drones could change by around 2016.
Emma Carr deputy director of privacy and civil liberties campaign group Big Brother Watch told The Huffington Post UK the group wanted to see "clear rules that establish what drones can be used and why, before we see our skies littered with flying cameras.
"It was only a matter of time before we saw military hardware re-designed to be used in civilian environments when there is no clear pressing reason to do so, other than the profits of the companies involved."