Drudger

Drudgers were hovering, armed robots, which were primarily used as security drones.

History
Bernice Summerfield used a Drudger to return the Pearl of Wisdom to the Slarvian Emperor. (PROSE: Benny and Louise)

On one planet, they reported back to Ruthley and assessed any visitors who stumbled across the hidden planet. They were also used for extinguishing fires. They would not kill unless provoked, remarking "that procedure is not permitted", but they did use an extremely painful mind scan on the Seventh Doctor and Elenya. They were then confronted by the assassins who had arrived to kill Sancroff, First Knight of Velyshaa; their firepower was useless against the assassins, and the Drudgers on the planet were presumably all destroyed. (AUDIO: The Sirens of Time)

Alby Brook's ship was equipped with a Drudger at the time of the Dalek invasion of Mutter's Spiral. (AUDIO: Invasion of the Daleks)

Space Dock Nerva was equipped with security Drudgers when it was visited by the Fourth Doctor and Leela. The Drudgers were armed with paralysis beams. (AUDIO: Destination: Nerva)

Mr. Dorrick made use of drudgers aboard a Conglomerate space platform. (AUDIO: The Pursuit of History / Casualties of Time)

Behind the scenes

 * The Drudgers originated in the Audio Visuals fan audio series.
 * Drudgers have been voiced by Nicholas Briggs, Ian Brooker, Tim Treloar, Jez Fielder and John Banks.