Peter Capaldi's 56th birthday was celebrated during the filming of this episode. In particular, he was presented with a Dalek-themed birthday cake.
Prior to the episode's airing, American journalists James Foley and Steven Sotloff were beheaded by ISIS. Executive producer Brian Minchin flagged the episode as having potentially problematic content. As a result, the climax was severely edited - the Doctor originally used a tapestry in the vault to incapacitate the Sheriff, allowing Robin to behead him. However, the Sheriff was revealed to be a cybernetic lifeform, having been rebuilt by the robots after their spaceship crashed directly on him. The Sheriff's body threatened Clara, prompting Robin to rescue her by restoring the man's head. The pair then proceeded to their duel on the beam. The BBC agreed with Minchin's concerns, and authorised a last-minute re-edit. The loss of the beheading meant that the episode was abbreviated by about one minute. Evidence of the omission remained in the sudden disappearance of the tapestry from the vault wall, and the Sheriff's description of himself as "the first of a new breed - half man, half engine".
When the Doctor and Clara are being introduced to Robin's Merry Men, the Doctor hypothesizes that they 'could be inside a Miniscope'. The Miniscope was first introduced in Carnival of Monsters: Episode One (1973).
Clara indicates that she is from Blackpool, which is the real life hometown of actress Jenna Coleman.
The sheriff's question "who will rid me of this turbulent doctor?" Is a reference to when Henry II, Richard Lionheart's predecessor, supposedly asked " who will rid me of this turbulent priest?" in 1170, twenty years before this episode is set. The question was interpreted as a command to murder Thomas Beckett, Archbishop of Canterbury.