Silver Dalek (Susan and the Daleks)

A Silver Dalek drone was present in the occupied London during the 2150s Dalek invasion of Earth.

This Dalek was patrolling Trafalgar Square with a Red Dalek leader when the latter noticed an unauthorised humanoid on a bench — Susan Foreman, who had unwittingly gone back to the middle of the invasion in the Doctor's TARDIS. She fled up a flight of stairs and took refuge in said TARDIS; the Red Dalek attempted to follow her up by hoverbout, but was too late to stop her escaping. However, it ordered that the Blue Chrono-Dalek give chase to the intruder. (TV: Susan and the Daleks)