Daisy Bell

"Daisy Bell" was a song performed at the Palace Theatre whilst the Fourth Doctor and Leela were attending. (TV: The Talons of Weng-Chiang) In 2367, Robots 1 and 2 sang this song when the Eleventh Doctor deactivated them. (TV: Dinosaurs on a Spaceship)

Behind the scenes
The robots singing "Daisy Bell" as they died is a reference to HAL doing the same in Arthur C. Clarke's film, which was itself a reference to the first song ever sung by a computer made by a human (the IBM 704) in 1961.