A 3ft police "spy drone" took to the skies in 2007 to help track crooks and record anti-social behaviour.

The crewless, remote-controlled helicopter uses CCTV to record images from 1,600ft above ground. It is virtually silent and has night vision to flush out suspects in the dark. Merseyside police were impressed after the drones were first used by the British Army. Assistant chief constable Simon Byrne said: "This is a cost-effective way of helping to catch criminals."