Tiny spy helicopter can swoop on criminals and mark them with a squirt for capture

It may look like a child's toy but this unmanned spy helicopter can swoop down and squirt criminals with a liquid marker so they can later be identified by police.

The £25,000 remote-controlled Microdrone, the size of a dustbin lid, can capture high-quality video footage and infrared imagery from more than 350ft away, beaming the data back to its operators on the ground.

But its most revolutionary function is to mark offenders with a solution called SmartWater which identifies them to police.

British Transport Police have been using the device, which took eight years to develop, as part of an operation to crack down on metal cable thefts on the railways, codenamed Operation Drum.

A BTP spokesman said: "Although it may look simple, it's actually a complex bit of kit capable of many things.

"There's only one being used at the moment as it is an expensive device." ...

He added: "The Microdrone will not be intrusive to the general public and will only be aimed at people involved in criminal activity."

Dyan Crowther, from Network Rail, said: "Sadly the theft of cable from the railways remains a serious and pressing issue for us. - dailymail