Doctor Who - The Doctor's Type Fifty

The Doctor's Type Fifty
Audio - Prisoners of Fate
Prisoners of Fate
(Jonathan Morris)
 Name: The Doctor's Type Fifty, posed as the Chronoscope on Valderon until 3556.

 Format: Audio

 Time of Origin: Originated from Gallifrey at the same time as the First Doctor's departure; encountered the Fifth Doctor on Valderon in 3556 after arriving there approximately twenty years prior.

 Appearances: "Prisoners of Fate"

 Doctors: Fifth Doctor; was used by the First Doctor before he left Gallifrey for good.

 Companions: Nyssa, Tegan Jovanka, Turlough; unclear if it would have had any contact with Susan given her complicated history.

 History: Although the fact that The Doctor stole the TARDIS has been common knowledge since he made contact with his people ("The War Games"), nobody ever wondered what he owned as a means of transport before he acquired the familiar Type Forty. It was eventually revealed that, before he departed Gallifrey, The Doctor's official TARDIS was a Type Fifty, but his decision to depart Gallifrey was so impulsive that The Doctor had no time to retrieve his existing TARDIS, instead stealing the familiar Type Forty and departing in that with Susan (Either leaving with her directly ("The Name of The Doctor") or collecting her from Gallifrey's distant past ("Lungbarrow")).

 Outraged at The Doctor leaving it in such a manner, the Type Fifty broke free of its dimensional stabilisers, burned out its recall circuits, jettisoned three quarters of its internal architectural configuration and ripped through the transduction barriers in order to follow its old owner. However, its dematerialisation circuit was so damaged by this escape that it was only able to make one trip that ended when it crash-landed on the planet Valderon, where its translation circuit went into overdrive, causing it to automatically translate every language on the planet. Shortly after this event, Sibor, the current ruler of the planet, discovered the crashed TARDIS, but when the ship attempted to communicate with her, its damaged condition meant that it could only express visions of the future. Seizing the opportunity for power presented by this ability, Sibor kept its existence secret, simply sharing the visions of the future in a controlled manner that allowed her to establish her authority over the planet​, presenting her source as the 'Chronoscope'. Realising that its continued existence depended on Sibor, the Type Fifty showed her a range of visions of the future that benefited her, allowing her to commit such acts as arresting people for crimes that the 'Chronoscope' predicted they would commit if left free (the evidence suggests that these visions of the future depicted at least a version of the future, as the visions shown after The Doctor arrived on Valderon did come true, although The Doctor noted that locking people up would make the visions of their crimes impossible most of the time). At some point, Sibor invited young physician Adric Traken to work on a cure for Richter's Syndrome, a dangerous plague that was ravaging the galaxy, but she only intended to use his work on the cure to subsequently blackmail herself into a position of greater power​, a strategy that the 'Chronoscope' assured her would work.

Audio - Cobwebs
(Jonathan Morris)
 When the Type Fifty detected The Doctor's current Type Forty passing by the planet, it triggered its remaining circuits to lure The Doctor's TARDIS to land on the planet. As a result, the Fifth Doctor emerged from the ship with Tegan, Turlough, and Nyssa, prompting Adric to make an understandable mistake; although Nyssa was currently travelling with The Doctor for the second time ("Cobwebs"), she had recently been physically regressed back to the age she had been when she originally travelled with the others ("The Emerald Tiger"), with the result that Adric believed that this version of his mother hadn't left the ship yet. Believing that this TARDIS crew were from a point before Nyssa left The Doctor on Terminus ("Terminus"), Adric spoke with Tegan in private to ask her to travel to the planet Helheim after the 'current' Nyssa left them, believing that she could thus rescue his mother without causing a paradox. However, before Tegan could discreetly explain the situation in full to The Doctor, the Chronoscope sent out a vision of Tegan and Turlough killing a guard so that they would be arrested and sent to the Citadel. Tegan's past experience with the Mara ("Kinda" and "Snakedance") and Turlough's more recent experience with Eldrad ("Eldrad Must Die!") had left them both more susceptible to mind control than the average, which gave the Chronoscope the chance to control them and make them act as its pilot.

Nyssa (Terminus)
 Meanwhile, Nyssa was exposed to the truth about the situation when Adric confronted her after Turlough unwittingly revealed the truth about Nyssa's current status, this knowledge ensuring that Nyssa couldn't go back to her family without creating a paradox. Despite Adric's bitterness at the idea that his mother had left her children behind to go travelling once again, he was able to work with his mother to find a cure for Richter's using samples Nyssa had acquired while travelling with The Doctor and data Adric had gathered during his own travels, but the two realised that this reaffirmed the fact that Nyssa could never go back, as Adric would never have gathered that data if Nyssa hadn't 'died' and prompted him to carry out his own research into the disease. While Nyssa worked with her son, The Doctor entered the prison to try and rescue Tegan and Turlough, only to learn the truth about the Chronoscope when he sensed its telepathic influence and was drawn to confront it directly. Hearing the Type Fifty's explanation for its arrival on Valderon, The Doctor agreed to take it back to Gallifrey to be repaired, but he was privately suspicious of it considering what it had done to date rather than take the simpler option of asking him for help directly.

 When Sibor learned of Nyssa and Adric's success in perfecting a cure for Richter's, she attempted to put her planned blackmail into action, but was then tricked into providing extra power to the Chronoscope, which allowed it to repair its damaged chameleon circuit. Likely due to its limited remaining resources, the Type Fifty was able to actually turn itself into a duplicate of Tegan, subsequently tricking Nyssa and The Doctor into taking it to The Doctor's Type Forty so that it could take control of its 'successor'. Now able to travel in time once again, the Type Fifty took the Type Forty back to the moment when Nyssa's family received the message that she was likely dead, convincing Nyssa to leave the ship before taking it back to Valderon. As a result of this change to history, the Type Fifty began to absorb the potential Blinovitch overload caused by the paradox of Nyssa returning to her family in 3531 when she already knew that wouldn't happen, going so far as to convert the prison building into part of itself, as well as draining energy from The Doctor's Type Forty after removing the dematerialisation circuit to replace its own. Had the process been allowed to complete itself, the resulting Blinovitch paradox would have created two versions of Valderon that would have destroyed themselves, as well as possibly several other planets whose histories would have been affected by Nyssa's research into the plague, restoring the Type Fifty at the cost of all these other worlds. Fortunately, the telepathic circuits were still strong enough for The Doctor to help Adric send a message back to his mother before she could introduce herself to his past self, allowing Adric to convince Nyssa to instead go into hiding and minimise her impact on history until she could return to Valderon to assist them further.

Peter Davison
The Fifth Doctor
 Although The Doctor's plan to eliminate the wider paradox succeeded, the Type Fifty was still able to gain power thanks to another temporal paradox he didn't know about; some time before rejoining the TARDIS crew, shortly after the birth of her daughter, Nyssa had made telepathic contact with the Fifth Doctor during his regeneration ("The Caves of Androzani" and "Circular Time: Winter"), but during that conversation he had expressed surprise upon learning that Nyssa was now a mother. The potential paradox of whether or not The Doctor knew that Nyssa would become a parent before that conversation was comparatively minor, but taking place at a moment when The Doctor's own future was already in doubt meant that it could potentially erase The Doctor's future incarnations- defined by the Type Fifty as 'the rhetorician (Sixth), the schemer (Seventh) and the idealist (Eighth)'- giving the Type Fifty another source of power to draw on. Fortunately, having clarified the relevant details of what would happen to him in the future Nyssa had experienced without learning too many specifics, The Doctor was able to conclude that he could simply feign ignorance of Nyssa's children during their 'talk' when he regenerated, thus eliminating that final paradox. With it now impossible for the Type Fifty to survive, as it could see no future for itself that ended in any way but its own death, The Doctor convinced it to take him back in time to the moment after Nyssa received that final psychic message from Adric, allowing him to take the younger Nyssa back to their time, erasing the twenty-five years she spent in hiding. Although the creation of this paradox would destroy the Type Fifty, it was an easier death than it would have experienced if The Doctor had done nothing, giving it time to return to Valderon and remove its stolen dematerialisation circuit so that The Doctor could repair the Type Forty.

 As the Type Fifty died, The Doctor apologised to the ship for abandoning it, but the Type Fifty acknowledged that it had probably worked out for the best, as the Time Lord would never have had the kind of adventures he had in the Type Forty if they had travelled together as the Type Fifty was too predictable (foreshadowing the TARDIS's later revelation to the Eleventh Doctor that, while it didn't always take The Doctor where he wanted to go, it would always take him where he needed to go ("The Doctor's Wife")).
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Parts of this article were compiled with the assistance of David Spence who can be contacted by e-mail at
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