Season 16

Season 16 of Doctor Who ran between 2 September 1978 and 24 February 1979. It starred Tom Baker as the Fourth Doctor, Mary Tamm as Romana I and John Leeson as K9 Mark II. The season opened with The Ribos Operation and concluded with The Armageddon Factor.

Overview
It consisted of six serials and twenty-six episodes. This season saw the introduction of the Black and White Guardians as well as the companion Romana I who became the first Time Lady companion since Susan. This season is sometimes colloquially known as The Key to Time season after the story arc involving the Key to Time. Although not the first season to consist of linked stories (Season 8 in 1971 was the first, as all the stories that year featured ), it was the first to be recognised as having a series-long arc. Although multi-serial arcs would occur again, such a full-season experiment wouldn't be attempted again until Season 23. The arc has a number of similarities to the Season 1 story The Keys of Marinus.

Season 16 marked a triple milestone for Doctor Who: the hundredth story (The Stones of Blood), the five-hundredth episode (episode 1 of The Armageddon Factor) and the fifteenth anniversary of the first broadcast, on 23 November 1978.

A number of publicity photos for the season show Tom Baker sporting a very obvious bandage on his upper lip; this was due to his being bit by a dog shortly before filming for the season began. The resulting lip injury is visible to varying degrees throughout the season.

In 2002 (Region 1) it became the first Doctor Who season to be released to DVD in its entirety in a single box set; it remained the only "classic series" season to be available as a single set until the release of Season 23, The Trial of a Time Lord to DVD in 2008.

Tom Baker decided to leave by the end of this season, however, he was persuaded to stay.

Television stories
{|

! # || Title || Writer || Episodes || Notes Dave Martin||6||Final appearance of Mary Tamm as Romana; first appearance of the Black Guardian; Lalla Ward's first role in Doctor Who. Final story on which Anthony Read was script editor and the final story to be written by Bob Baker and Dave Martin, although Baker would write a solo story the following season.|}
 * 1 ||The Ribos Operation||Robert Holmes||4||First appearance of Romana. First appearance of the White Guardian.
 * 2 ||The Pirate Planet||Douglas Adams||4|| First story to written by Douglas Adams and the only televised story where he received sole credit.
 * 3 ||The Stones of Blood||David Fisher||4|| Marks Doctor Who's one hundredth television story. Part four aired during the fifteenth anniversary of the series. First story to be written by David Fisher.
 * 4 ||The Androids of Tara||David Fisher||4|| Parody of . Mary Tamm plays four different roles in this story; Romana, Princess Strella, and android doubles for both characters.
 * 5 ||The Power of Kroll||Robert Holmes||4|| K9 is absent during this story due to his prop's inability to manoeuver in the swampy location of the episode.
 * 6 ||The Armageddon Factor||Bob Baker
 * 4 ||The Androids of Tara||David Fisher||4|| Parody of . Mary Tamm plays four different roles in this story; Romana, Princess Strella, and android doubles for both characters.
 * 5 ||The Power of Kroll||Robert Holmes||4|| K9 is absent during this story due to his prop's inability to manoeuver in the swampy location of the episode.
 * 6 ||The Armageddon Factor||Bob Baker
 * 5 ||The Power of Kroll||Robert Holmes||4|| K9 is absent during this story due to his prop's inability to manoeuver in the swampy location of the episode.
 * 6 ||The Armageddon Factor||Bob Baker
 * 6 ||The Armageddon Factor||Bob Baker

Cast

 * Doctor Who - Tom Baker
 * Romana I - Mary Tamm
 * K9 - John Leeson

Recurring

 * The Guardian - Cyril Luckham
 * The Guardian - Valentine Dyall

Guest

 * Garron - Iain Cuthbertson
 * Unstoffe - Nigel Plaskitt
 * Graff Vynda-K - Paul Seed
 * Sholakh - Robert Keegan
 * Binro - Timothy Bateson
 * Captain - Bruce Purchase
 * Mr. Fibuli - Andrew Robertson
 * Kimus - David Warwick
 * Mula - Primi Townsend
 * Nurse - Rosalind Lloyd
 * Professor Rumford - Beatrix Lehmann
 * Vivien Fay - Susan Engel
 * De Vries - Nicholas McArdle
 * Martha - Elaine Ives-Cameron
 * Megara Voices - Gerald Cross, David McAlister
 * Count Grendel - Peter Jeffrey
 * Zadek - Simon Lack
 * Prince Reynart - Neville Jason
 * Princess Strella - Mary Tamm
 * Farrah - Paul Lavers
 * Lamia - Lois Baxter
 * Till - Declan Mulholland
 * Archimandrite - Cyril Shaps
 * Thawn - Neil McCarthy
 * Fenner - Philip Madoc
 * Dugeen - John Leeson
 * Rohm-Dutt - Glyn Owen
 * Ranquin - John Abineri
 * Varlik - Carl Rigg
 * Skart - Frank Jarvis
 * Harg - Grahame Mallard
 * Marshal - John Woodvine
 * Princess Astra - Lalla Ward
 * Merak - Ian Saynor
 * Shapp - Davyd Harries
 * The Shadow - William Squire
 * Pilot - Pat Gorman
 * Drax - Barry Jackson

Stories set during this season

 * PROSE: Tomb of Valdemar (between The Ribos Operation and The Pirate Planet)
 * PROSE: The Shadow of Weng-Chiang (between The Stones of Blood and The Androids of Tara)
 * PROSE: Heart of TARDIS (between The Stones of Blood and The Androids of Tara)
 * AUDIO: Ferril's Folly (between The Stones of Blood and The Androids of Tara)
 * PROSE: X-Rani and the Ugly Mutants (between The Androids of Tara and The Power of Kroll)
 * PROSE: Light Fantastic (between The Androids of Tara and The Power of Kroll)
 * PROSE: Reluctant Warriors (between The Androids of Tara and The Power of Kroll)
 * COMIC: The Weapon (between The Androids of Tara and The Power of Kroll)
 * PROSE: Return of the Electrids (between The Androids of Tara and The Power of Kroll)
 * PROSE: The Sleeping Guardians (between The Androids of Tara and The Power of Kroll)
 * AUDIO: Luna Romana (partially set between The Power of Kroll and The Armageddon Factor)

VHS

 * The Ribos Operation
 * The Pirate Planet
 * The Stones of Blood
 * The Androids of Tara
 * The Power of Kroll
 * The Armageddon Factor
 * The Tom Baker Years (excerpts from all stories)

DVD
This entire season was released with minimal restoration and extras in region 1 only on 1 October 2002 as a box set and was available individually. A limited edition box set with full restoration and expanded extras was released in region 2 on 24 September 2007. This limited edition version was later issued as the 7 November 2007 region 4 release, the 3 March 2009 region 1 "Special Edition" release (these were also available individually), and the 16 November 2009 non-limited region 2 re-release.

Novels
Target Books was unable to come to an agreement with Douglas Adams to novelise his script, The Pirate Planet. It was finally adapted by BBC Books in 2017.
 * Doctor Who and the Ribos Operation
 * The Pirate Planet
 * Doctor Who and the Stones of Blood
 * Doctor Who and the Androids of Tara
 * Doctor Who and the Power of Kroll
 * Doctor Who and the Armageddon Factor