The Clockwork Repair Droids were androids that served on the SS Madame de Pompadour and its sister ship, the SS Marie Antoinette. The former stalked Madame de Pompadour in 18th century France, believing that they could repair their ship by taking her brain. They wore 18th century French clothing to blend in with the people of the era and were clockwork instead of electric so they could function if their ship's power was depleted. The latter crashed and remained hidden until the Victorian London when their leader tried to repair the ship to take them to the promised land.
Characteristics
They followed camouflage procedures to blend into the surroundings by dressing in somewhat unrealistic 18th century costumes. They were equipped with short range teleporters, scanners, tranquillisers and sharp tools within their wrists for part removal. They could also heat themselves if they were frozen and empty unwanted fluids from their system. Whenever they entered a room, they made "tick tock" noises from their clockwork parts. They broke any clock in the room to avoid raising suspicion. (WC: Tardisode 4, TV: The Girl in the Fireplace) The crew of the SS Marie Antoinette however, used human skin and harvested organs as spare parts. (TV: Deep Breath)
History
The Droids' only purpose was to fix the ship. When the ship was damaged in the Dagmar Cluster in an ion storm, they lacked the right parts. They used the crew members' body parts; according to the Tenth Doctor, "No-one told [them] the crew weren't on the menu." The last part they needed was a brain for their command circuit, and they believed that only the thirty-seven-year-old brain (the same age of their ship) of Madame de Pompadour would work. They modified the ship's warp engines to open many time windows to 18th century France and passed through it at various moments of Madame de Pompadour's life, attempting to find her in her thirty-seventh year. The Doctor defeated them by disconnecting the time window that led back to their ship. With no purpose, they shut down. (TV: The Girl in the Fireplace)
When Es'Cartrss tried to take over the Tenth Doctor's mind via the TARDIS' Matrix, he used his memories of the Clockwork Droids to attack him. (COMIC: The Forgotten)
Other Clockwork Droids
The Doctor encountered a different type of clockwork android during his ninth incarnation. Shade Vassily made an almost perfect human-looking clockwork droid (Repple) to distract anyone who came looking for him, but the Doctor figured out he was clockwork. Clockwork Cats which shot lasers out of their eyes protected Vassily, but the Doctor and Melissa Heart reprogrammed one. Melissa also had two clockwork knights to do her bidding, both of which were destroyed; one was used to repair the clockwork cat, and the other sacrificed itself to save London. (PROSE: The Clockwise Man)