Councils may start using drones to snoop on people's home extensions if they suspect they have built them too large.

The Telegraph has found that dozens of district councils have received commercial drone licences from the Civil Aviation Authority.

The developments have prompted concern from civil liberties campaigners who described council drones as an “expansion of state surveillance”.

The campaign group Big Brother Watch called for guidelines to be drawn up to ensure drones were not used to spy on taxpayers without “good reason”.

Silkie Carlo, the director of Big Brother Watch, said: “There’s a real risk that drones could be used by councils to expand the surveillance state.

“There should be clear safeguards in place to make sure authorities make the best of new technologies without having free license to snoop on the public in the absence of good reason.”

Councils across the country already use drones for a number of functions such as investigating fly tipping.

Among them is North Yorkshire County Council, which recently invested almost £2,000 in one of the devices, which is to be licensed by the Civil Aviation Authority.

The council told The Telegraph the device would be used for a range of enforcement activities including “inspecting poor roofing work by a rogue trader, flying over open land looking for livestock carcasses or inspecting sites in relation to breaches of planning controls that the county council enforces.”