As well as being the first story of the ‘Twentieth Anniversary’ season "Arc of Infinity" is best remembered for containing the return of companion Tegan Jovanka to the show (after she was seen to depart from the TARDIS at the end of the previous story, "Time-Flight") but also the second time in the show’s history that a story had been filmed outside of the United Kingdom – as parts of this story were filmed on location in Amsterdam, Holland.
Johnny Byrne - whose first Doctor Who story had been "The Keeper of Traken" - was invited to contribute the opening story for Season Twenty, and as a result he was asked to incorporate certain elements into his submission. First, he had to reunite companion Tegan with The Doctor and Nyssa. This was because at the end of the Season Nineteen finale, "Time-Flight", Tegan had been left behind on Earth by The Doctor. Tegan’s departure from the TARDIS was used as a cliffhanger to maintain viewer interest during the nine-month break between seasons.
Because Producer John Nathan-Turner wanted to take Doctor Who overseas, for just the second time in its history, Johnny Byrne was asked to incorporate this in the storyline. The previous oversees recording occurred in the 1979 Fourth Doctor story "City of Death". This had been on location in Paris, France. The venue John Nathan-Turner had in mind for "Arc of Infinity" was Amsterdam in Holland - one of the locales used by the BBC soap opera Triangle. In order to justify the trip, Johnny Byrne was asked to make the Dutch city a key aspect of his storyline. To reintroduce Tegan, in the second episode, Johnny Bryan had her being in Amsterdam on holiday and accidentally coming across some form of criminal activity which would require The Doctor’s attention (Producer John Nathan-Turner insisted that such activity should not be drug smuggling, theft of diamonds or Old Dutch Masters, or anything political).
The director assigned to this story was Ron Jones, who had last worked on "Time-Flight". On top of handling the highly-publicised foreign filming, Ron Jones had an additional responsibility in that Johnny Byrne had left the climactic fourth episode chase scene largely unscripted, because it was impossible for him to forecast weather and crowd conditions. As a result, Ron Jones had to basically create these scenes himself as he went along, with such elements as the raising bridge coming at the spur of the moment. Crowd control also proved an issue, with Dutch viewers recognising Peter Davison from his role as Tristan Farnon in All Creatures Great and Small.
This resulted in a cameo appearance by Producer John Nathan-Turner, in the scene where The Doctor and Nyssa are in a telephone booth, when he becomes visible in the background trying to shoo onlookers away.
Although "Arc of Infinity" was planned as the first story of the new season, it was decided early on to record it second after "Snakedance" in order to take advantage of the better weather in May and June. Ultimately, location shooting in Amsterdam was scheduled for May 1982.
The location shooting in Amsterdam was carried out at: Muntplein, Herengracht, Leidseplein, Nieuwezijds Voorburgwal, Zandpad, Middenweg, Prinsengracht, Amstel Sluize, Stationsplein, Schiphol Airport, Singel, Lijnbaansgracht, Sint Nicolaasstraat, Amstelveld, Frankendael House (Middenweg 172), Amstel, and Dam Square.
This story is contains the second, of two stories, where the main villain is Omega. Aware of the success he had enjoyed in bringing back The Master in the 1981 Fourth Doctor story "The Keeper of Traken", Producer John Nathan-Turner wanted his season opener to feature another old enemy. Omega, another renegade Time Lord, had previously appeared in the 1973 special Tenth Anniversary story "The Three Doctors". The idea to bring Omega back was suggested by fan consultant Ian Levine, while overseas filming was an idea from John Nathan-Turner and a story returning to Gallifrey was the concept of Script Editor Eric Saward.
In "The Three Doctors" actor Stephen Thorne had played the part of Omega. Whereas in this story the part of Omega was played by Ian Collier. Ian Collier had appeared once before in the show, as Stuart Hyde in the 1972 Third Doctor story "The Time Monster".
In order to preserve the surprise of Omega’s identity, it was decided to bill the character as "The Renegade" for the first two episodes so as not to spoil the surprise of this characters return to the show.
This story boasted two important guest starring roles: Michael Gough (playing the part of Councillor Hedin) had previously portrayed the Celestial Toymaker in the 1966 First Doctor story "The Celestial Toymaker". Michael Gough later achieved international fame in the Batman movies as Alfred Pennyworth, the Wayne Manor butler). Michael Gough had also been married to Anneke Wills (who played companion Polly).
The second guest star was Colin Baker (playing the part of Commander Maxil). Colin Baker had been suggested to play this part by Assistant Floor Manager Lynn Richards on the basis of his role in the Blake’s 7 story "City at the Edge of the World". Other actors under consideration for this part included Tim Woodward and future Remington Steele and James Bond actor Pierce Brosnan.
It was his performance in this role (which, according to Colin Baker, Producer John Nathan-Turner repeatedly told him to ‘tone down’) that first brought him to the attention of the production office. It has since been revealed that Colin Baker commented at the time to his wife that his guest appearance in this story would probably preclude him from ever taking over the role of The Doctor - a notion that would prove wrong two years later when Colin Baker became the Sixth Doctor.
Ironically Colin Baker also gets to shoot the Fifth Doctor in the closing scene of the first episode.
The character of Borusa (last seen in the 1976 Fourth Doctor story "The Deadly Assassin") was reintroduced, now Lord President (the use of a different actor (Leonard Sachs) was explained by the fact that this character had regenerated. Leonard Sachs, previously played the part of Admiral de Coligny in the 1966 First Doctor story "The Massacre of St Bartholomew's Eve". Actor John Horsley was also a contender for the role of President Borusa.
The decision was made to identify the Lord President of the High Council as Borusa, The Doctor's former teacher who had previously appeared in the Fourth Doctor stories "The Deadly Assassin (1976) and "The Invasion of Time" (1978).
This story’s Castellan, played by Paul Jerrico, would return in the Twentieth Anniversary story "The Five Doctors".
It is not explained how Omega survived the events of "The Three Doctors", beyond Councillor Hedin’s unhelpfully dogmatic statement – ‘No, he exists’.
It is revealed that he has acquired a TARDIS and in order to remain in our Universe, Omega needs to bond with a Time Lord, thus reversing his polarity, and to that end he persuades Councillor Hedin to steal and transmit The Doctor’s bio-data extract (see "The Deadly Assassin").
It is also revealed that Omega left the anti-matter universe in the region known as Rondel, ‘the gateway to the dimensions’. According to the TARDIS information banks Rondel is an intergalactic region devoid of all stellar activity, and formerly the location of a collapsed 'Q' star (so named because such imploding stars emit Quad magnetism, the only known 'shield' for anti matter, although it decays very rapidly). This region’s colloquial name is the Arc of Infinity.
At one point Nyssa is heard to state that the TARDIS navigation system needs some repairs, damage having been caused by the Cybermen in "Earthshock" (although it seems that The Doctor is able to pilot it successfully to Amsterdam).
During this story the TARDIS is recalled to Gallifrey. This is only the third time in the history of the Time Lords that a recall circuit has actually been used (see "The Deadly Assassin"). Once on Gallifrey, The Doctor’s TARDIS is incapacitated by the removal of the main space-time element from under the console, although this is later replaced by Damon.
Damon is a friend of The Doctor and it is implied that The Doctor met him (not necessarily for the first time) during the events of "The Invasion of Time".
A traitor at work on Gallifrey was also used as a plot device in "The Deadly Assassin" and would again be used in "The Five Doctors".
Although capital punishment has long been abolished on Gallifrey (see "The Deadly Assassin"), it seems a single precedent for The Doctor’s termination does exist.
It is stated that The Doctor’s execution in this story is only the second time in Time Lord history that the race has sentenced one of its own to death, the first being the renegade Time Lord Morbius from the 1976 Fourth Doctor story "The Brain of Morbius". The Doctor also becomes the second Time Lord to survive termination, and once more finds himself in the Matrix (which The Doctor last entered in "The Deadly Assassin").
The Doctor’s failure to return Romana to Gallifrey, as seen in "Warriors' Gate", is mentioned briefly when Thalia comments on The Doctor's inability to carry out this summons. The Doctor replies by telling Thalia that Romana chose to stay in E-Space.
Leela’s decision to remain behind at the end of "The Invasion of Time" is also mentioned when The Doctor is heard to ask Damon about his former travelling companion and expresses regret that he could not get to her wedding.
New regular costumes for Nyssa and Tegan are seen for the first time in this story. (Although Tegan’s new costume makes its debut here, Nyssa’s is not seen until the following story, "Snakedance". This myth derives from the fact that numerous publicity photographs of the two actresses wearing their new costumes were taken during the location shoot in Amsterdam. These photo shoots were made possible by the fact that "Snakedance" was filmed before "Arc of Infinity").
The dress worn by Nyssa at Cranleigh Hall, in "Black Orchid", can be seen in her room.
It is revealed that Tegan has lost her job and was hoping that meeting Colin Frazer, her favourite cousin, would cheer her up. Like Tegan, Colin comes from Brisbane in Australia.
Though Tegan only departed at the end of the previous story, "Time-Flight", The Doctor and Nyssa travelled without her in stories in other media.
Tegan is not the first companion to have rejoined the TARDIS after having departed. The first companion to return to the show was Harry Sullivan who opted to remain on Earth at the end of the 1975 Fourth Doctor story "Terror of the Zygons", and reappeared in later that season in "The Android Invasion". Other previous characters have also left the show and then returned. This includes: The Brigadier, Sergeant Benton and Captain Mike Yates. In the revived show, Sarah Jane Smith, Captain Jack Harkness, Mickey Smith, Donna Noble, Martha Jones and Rose Tyler have all made reappearances.
As had been done with Season Nineteen, Season Twenty was aired two nights a week. Although the Wednesday broadcast would be maintained it was decided to shift the other weekly broadcast from the Monday to the Tuesday. The only exception was the first episode of this story which was still shown on the Monday.
A double-pack DVD featuring both this story and "Time-Flight" was released in August 2007. The DVD for "Arc of Infinity" contains an option to view this story with CGI enhanced special effects sequences. This DVD also features a commentary with Peter Davison, Colin Baker, Janet Fielding, and Sarah Sutton. It is the only commentary to date that features two actors who have played The Doctor.
The cover for this double-pack DVD release shows the "Peter Davison Years" as being from ‘1981-1984’. All other Fifth Doctor releases have claimed the years as ‘1982-1984’, in deference to the January 1982 broadcast of "Castrovalva". However, there is justification for calling the era ‘1981-1984’, as that wass the period of time Peter Davison actually worked on the programme. Like Jon Pertwee who played the Third Doctor, Peter Davison fell victim to the BBC’s decision to push back the premiere of his first season to the start of the new calendar year. Neither actor is generally credited for their first year on the job, making their time in the show appear a little shorter than they actually were. While Jon Pertwee only filmed about half of Season Seven in 1969, almost everything of Season Nineteen was filmed in 1981. Indeed, Peter Davison’s first work on the show - his regeneration scene - had been filmed in January 1981, almost a full year prior to the release of "Castrovalva". Ironically, the only part of Peter Davison’s initial year not filmed in 1981 was this lone story. All told, Peter Davison’s time in front of the cameras as The Doctor lasted from 9th January 1981 to 12th January 1984 - almost precisely the three-year tenure, that it has been revealed, that he had been advised by Patrick Troughton, who played the Second Doctor, to undertake.
Colin Baker reprised the role of Commander Maxil as an uncredited cameo in the 2006 Big Finish Productions Gallifrey audio story "Appropriation".
The Doctor isn’t quite finished with Omega, as heard in the 2003 Big Finish Productions audio story "Omega", which takes place shortly after this story.
Hedin and Omega appear in the BBC Books’ The Past Doctors Stories novel "The Infinity Doctors" written by Lance Parkin.
Footage of The Doctor from this story appears in the projection from the Cybermen’s datastamp in the 2008 Tenth Doctor story "The Next Doctor".
The first story of Season Twenty.
The first appearance of Colin Baker, in the role of Commander Maxil, before he became the Sixth Doctor.
The first appearance of Omega for 10 years - since the 1973 Tenth Anniversary story "The Three Doctors".
The first appearance of President Borusa for 5 years - since the 1978 Fourth Doctor story "The Deadly Assassin".
June Collins's first involvement in the show as Production Unit Manager.