This episode was wiped by the BBC and no copy of it is known to exist.
Deborah Watling's appearance as Victoria was a recap from the end of Fury from the Deep: Episode 6 (1968). Unusually, she received an on-screen credit for this appearance.
This episode takes place aboard Space Station W3 in the 21st Century.
This is the only serial directed by Tristan de Vere Cole, who went on to become one of the UK's most prolific drama directors. He had previously been a production assistant during the William Hartnell era. He was reluctant to direct this, having previously directed a classic serial, and considered directing Doctor Who at the time something of a comedown from that.
11 minutes of this episode were animated as [title=tt10047426], using the original audio with new 2D animation. The mini-episode premiered at the BFI's annual Missing Believed Wiped event in 2018, before being released on DVD and Blu-ray with the animated version of "The Macra Terror" in 2019.