CIA spooks tried to spy on Soviet Russia using CATS implanted with microphones under their skin.

Declassified docs show how spy chiefs praised "pioneering" scientists for slitting open moggies and stitching in electronic hardware to uncover their enemies' secrets.

Dubbed "Project Acoustic Kitty", the grim £10 million programme was developed over five years in the 1960s as a novel but gruesome new eavesdropping method.

A cat's tail was used as an antenna and a wire travelled all the way up its spine connecting to a microphone in its ear, while a battery was housed in its chest.

But on its first test, its CIA handlers watched on in horror as their robo-kitty was run over and killed just seconds into the mission.