Don’t you understand?  This regeneration is failing!

The Fifth Doctor


The Doctor’s new regeneration has proved more unstable than previously, and looks to recuperate with the help of Tegan and Nyssa.  Meanwhile, Adric has been captured by the Master, who has set a  recursive trap designed to destroy the new Doctor’s mind.


Castrovalva can be split into a story of two halves – the story of trying to find the Zero Room and the story of Castrovalva – which are both plans to unravel the new Doctor’s mind by the Master.  This is something quite unusual in terms of modern episodes featuring the Master, as run times tend to mean he has only has one plan.  Anthony Ainley’s Master here is really quite menacing, especially in the first two parts when he captures Adric.  The makeup on him is also pretty good and the reveal of his disguise as the Portreeve in part 4 is handled really well.


This is also the most turbulent regeneration story that we have seen to date – the Fifth Doctor seems almost completely unhinged and it is his hunt for the Zero Room to help stablise his new body that occupies most of the first two parts of the episode.  We get some fantastic quotes about regeneration in the beginning, especially:

That’s the trouble with regeneration.  You never know what you’re going to get.

The Fifth Doctor

There’s also the symbolism of the new Doctor unraveling the iconic scarf to enable him to find his way back to the console room, which symbolises the Doctor’s deteriorating mental state. We also get Davison revisiting his past incarnations, which is quite good fun and the first time this really happens in the ‘classic’ era of Doctor Who.

In the Fifth Doctor era, there is always a problem of the companions.  Many critics of this part of the show’s history claim that the TARDIS is too full and that many writers do not know what to do with all three companions.  To a certain extent, this is true of Castrovalva, however, I find the use of Adric to be quite creative and Bidmead does do a good job of giving Tegan and Nyssa something to do to help the Doctor’s regeneration along.  This does make sense too, as these are the Doctor’s newest companions, so they should be thrust almost front and centre with the new Doctor. Despite this, it does seem a bit bizarre that Tegan is so doting over a man she barely knows.  Whilst making my notes, I noticed a similarity between the trap the Master has Adric in and Ebony Maw torturing Doctor Strange in Infinity War…or maybe that’s just my mind in geek overdrive.

Adric trap

Another strong aspect of this story is the idea behind the recursion trap, in which Castrovalva folds in on itself to keep the Doctor entrapped.  This does so perfectly encapsulate the idea of Doctor Who dealing with science fact, rather than some of the ludicrous stories that became common in the late Tom Baker era.  All in all, most of Bidmead’s work here is good, despite the two earlier parts being less interesting than the second two parts.

Verdict: A good introduction to the Fifth Doctor, whose post-regenerative trauma leads to quite an interesting story.  7/10

Cast: Peter Davison (The Doctor), Sarah Sutton (Nyssa), Janet Fielding (Tegan Jovanka), Matthew Waterhouse (Adric), Anthony Ainley (The Master), Derek Waring, Michael Sheard, Frank Wylie, “Neil Toynay” (The Portreeve)

Writer: Christopher H Bidmead

Director: Fiona Cumming

Producer: John Nathan-Turner

Composer: Paddy Kingsland

Parts: 4

Broadcast Dates: 4 – 12 January 1982

Behind the Scenes

  • Peter Davison is the first of three Doctors cast by producer John Nathan-Turner and they had previously worked together on All Creatures Great and Small.  Nathan-Turner had been involved in Doctor Who on and off since 1969 and took a regular role under his predecessor as producer, Graham Williams.
  • Davison would be the youngest actor to take the part of The Doctor at the age of 29 until the casting of Matt Smith in 2009.
  • There were issues with the initially planned debut story for the Fifth Doctor, Project Zeta Sigma, which would ultimately prove to be unworkable.  Castrovalva was the fourth story in the season to go into production, allowing Davison to make decisions as to how his incarnation would behave before making this story.
  • Castrovalva is the first story in the history of Doctor Who to credit the lead character as The Doctor rather than Doctor Who.  This was at the request of Peter Davison and would remain until the cancellation of the show in 1989.  Upon the 2005 revival, the credit reverted to ‘Doctor Who’ for the first series, however, on the insistence of incoming Tenth Doctor, David Tennant, the credit changed back to ‘The Doctor’.
  • This story saw the airing of the episodes shift from the traditional Saturday broadcast slot to being aired on Monday and Tuesday.
  • The Master appears in disguise as The Portreeve for a large amount of the story.  He is credited as “Neil Toynay”, an anagram of Anthony Ainley.

Cast Notes

  • This story marks the fifth appearance of Michael Sheard (The ArkThe Mind of EvilPyramids of Mars and The Invisible Enemy).  He would go on to make his final appearance in Remembrance of the Daleks.
  • Dallas Cavell previously appeared in The Reign of Terror, The Daleks’ Master Plan, The Highlanders and The Ambassadors of Death.

Best Moment

A toss-up between the Doctor looking at his new face in the mirror and the moment they realise the nature of Castrovalva’s trap.

Best Quote

I’m the Doctor.  Or I will be, if this regeneration works out.

The Fifth Doctor

Next story: Four To Doomsday

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