Substantial portions of the story were filmed on location in Amsterdam. This was only the second time the show had filmed outside of Britain. John Nathan-Turner hoped to repeat the success of the first story filmed overseas, City of Death (1979). Amsterdam was chosen both because the BBC had recently developed contacts there and because it was cheap to arrange travel and hotel accommodations. Story writer Johnny Byrne had some trouble at first because the producers wanted a plot that made the Amsterdam setting a key factor in the course of events, rather than him just happening to be there.
Cast notes
The story features a guest appearance by Michael Gough (who had previously played the Celestial Toymaker in the story of the same name).[4] Leonard Sachs previously played Admiral Gaspard de Coligny in The Massacre of St Bartholomew's Eve (1966).[2] Ian Collier previously played Stuart Hyde in The Time Monster (1972).[4]
Colin Baker (who would later portray the Sixth Doctor) appeared in the serial as Commander Maxil.[4] It was his performance in this role (which, according to Baker, producer John Nathan-Turner repeatedly told him to "tone down") that first brought him to the attention of the production office. Shortly after the production, the Assistant Floor Manager on the serial, Lynn Richards, invited Colin Baker to her wedding reception. Baker has said in a number of interviews that his entertaining form at the party directly led to his being cast as the Sixth Doctor the following year. Baker reprised the role of Maxil as a cameo in the 2006 Big Finish Productions audio play Gallifrey: Appropriation.[5] Colin Baker stated on Doctor Who: The Colin Baker Years video that John Nathan-Turner believed his performance was a little arch, and therefore gave him the nickname of Archie.
Elspet Gray, who played Thalia, later played Hera in the audio play Immortal Beloved. At the Fifth Element convention in London in February 2010, Alastair Cumming (who played Colin Frazer) explained that he is not related to Fiona Cumming (director of the Fifth Doctor serials Castrovalva (1982), Snakedance, Enlightenment (both 1983) and Planet of Fire (1984)), despite frequent reports that she was his mother.
According to the extensive production documentation released from the archive as part of the Season 20 - The Collection Box Set in September 2023, Colin Baker was originally considered for the part of the Castellan, alongside Bernard Hepton, Derek Godfrey, Patrick Stewart, Francis Matthews, Morris Perry, Keith Michell, Terrence Hardiman, Anton Rodgers, Peter Vaughan, Edward Woodward, Charles Kay, Sean Arnold and Peter Gilmore.
This is the third appearance of the Doctor's tutor Borusa, now Lord President.[2]
Actors considered for the role of Lord President Borusa were Peter Cushing who had played 'Doctor Who' in two 1960's movies featuring The Daleks; Michael Lees, Robin Bailey, Geoffrey Bayldon, Andrew Cruickshank, John Horsley, Bernard Archard, Richard Vernon, Terence Alexander and David Langton.
Alan MacNaughtan, William Fox, Donald Bisset, Glyn Owen, Richard Leech, William Lucas, Jonathan Newth, Jeffery Dench, Maurice Denham and Conrad Phillips were all considered for the role of Hedin.
Jonathan Newth was also suggested for the part of Omega, along with Malcolm Stoddard and Stephen Riddle. Honor Blackman, Jennie Linden and Lynda Bellingham were all shortlisted for the part of Thalia, with Pierce Brosnan and Tim Woodward being shortlisted for Maxil. The documentation does list whether or not some of the actors were available for the recording dates, but does not reveal if any offers were made or how final decisions on casting were reached.[6]
Leela, the fourth Doctor's previous companion who remained on Gallifrey at the conclusion of her final televised story, is mentioned in the script, but the production documentation makes no reference to her character ever being scheduled to appear in the story.[7]
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