For each episode, the title zooms up to the audience.

For the first time on the end titles, the Doctor is credited as "Doctor Who" rather than "Dr. Who".

For the first time, the end credits are superimposed against the title sequence backdrop rather than being rolled up against a black screen.

From this episode onwards, the series was produced in colour.

Autons created by Robert Holmes.

In 2006 this episode was released by The Sun free along with Robots of Death Part 1, Earthshock Part 1, The Faceless Ones Part 1, A Day of Armageddon and Rose.

This epiosde marks the first appearances of The Doctor, Liz Shaw, The Autons and the Nestene Consciousness.

Story Working title: Facsimilie

This episode attracted 8.4 million viewers on initial broadcast.

Although the Third Doctor is considerably taller than his previous incarnation, the Second Doctor's outfit still fits him perfectly.