Scientists running a pioneering experiment with "living robots" which think for themselves said they were amazed to find one escaping from the centre where it "lives".

The small unit, called Gaak, was one of 12 taking part in a "survival of the fittest" test at the Magna science centre in Rotherham, South Yorkshire, which has been running since March.

Gaak made its bid for freedom yesterday after it had been taken out of the arena where hundreds of visitors watch the machines learning as they do daily battle for minor repairs.

Professor Noel Sharkey said he turned his back on the drone and returned 15 minutes later to find it had forced its way out of the small make-shift paddock it was being kept in.