Britain's first remote control police aircraft, dubbed the "spy drone", took to the skies today.

The unmanned CCTV drone, which measures only a metre wide, is fitted with the latest in CCTV cameras and can record images from a height of 500m.

It was originally designed for military reconnaissance but is being used in a trial by Merseyside police to monitor public disorder, large crowds and traffic congestion. The force will also be looking at how the drone could be used during firearms operations and in efforts to reduce anti-social behaviour.

The controversial new spy plane was launched a day after Ian Readhead, the deputy chief constable of Hampshire police, warned that Britain risked becoming a surveillance society.

He said Britain faced an Orwellian style system of spying with cameras on every street corner.

But police in Merseyside insisted that the drone did not represent the next phase in creating a Big Brother society.

Assistant chief constable Simon Byrne said: "People clamour for the feeling of safety which cameras give. Our feedback from the public is anything we can do to fight crime is a good thing.

"There are safeguards in place legally covering the use of CCTV and the higher the level of intrusion, the higher the level of authority needed within the police force to use it. So there is that balance there."

The miniature helicopter, classified as an unmanned aerial vehicle, is almost silent when in use and is fitted with night-vision cameras to enable operators to carry out surveillance after dark.

It can be airborne in less than three minutes and the high-quality digital images it records can be instantly transmitted to a support vehicle or control room.

Alistair Fox, from Stoke-on-Trent-based MW Power, which supplies the drone in the UK, said the device was not restricted by civil aviation requirements and could either be flown by remote control or by using pre-programmed GPS navigation systems.

"It is much easier to control than an ordinary remote-controlled helicopter. It's pretty much forward, back, left, right and record," he said.

"They are military derived and obviously I can't talk too much about that particular use but they are essentially reconnaissance tools.

"They have been used in Germany for eight years and we have been involved with them for about six months."

Police said the drone was expected to be fully operational next month and would be given a three-month trial.