As the drone whirrs into the sky, something unusual trails behind it: a fibre optic cable barely visible to the naked eye.

The other end of the cable is attached to a pilot using a remote control unit to guide the first-person view machine toward its target: a Ukrainian armoured vehicle on the roadside.

Such fibre optic drones are the latest example of low-tech solutions being used to combat hi-tech electronic warfare (EW) on the battlefield.

Hundreds of miles of the front lines in Ukraine are covered by invisible, but almost impenetrable, shields of electronic pulses that knock drones out of the sky.