1986

History of the Doctor Who Universe
By this year International Space Command had regular Lunar flights and maintained a tracking station in Antarctica (DW: The Tenth Planet)

December
Humans first detect the Planet Mondas returning to the solar system, while it apparently was in orbit between Mars and Venus. The manned atmospheric probe Zeus IV is destroyed by the Cybermen inhabitants, and they go on to launch an attack on the Earth, starting with the Snowcap base in Antarctica. They plan to use a Z-bomb located here to destroy the Earth as one of their two worlds needed to be destroyed to save the other, but when they fail, Mondas is destroyed instead.

The doctor was present during this events and the strain it put on him trigered the regeneration from his first incarnation into his second. (DW: The Tenth Planet)

February

 * 22 - Donald Eccles (Krasis in The Time Monster) is killed in a road accident in Brighton, England, UK.

June

 * 11 - Reed De Rouen, who played Pa Clanton in "The Gunfighters," dies.

September

 * 06 - The Mysterious Planet Episode 1 First Broadcast (The Trial of a Time Lord Episode 1). The series returns to its original 25-minute episode format and the number of episodes per season is increased from 13 to 14. However, given the actual episode length reverted back to 25 minutes, this has resulted in a considerably shortened season in comparison to the 1984 and previous seasons. Trial of a Time Lord, although not the first season to consist of a single story arc (see The Key to Time), this is the first time only one on-screen title would be used for the entire season, although the fanbase and producers would divide the tale into four stories.


 * 13 - The Mysterious Planet Episode 2 First Broadcast (The Trial of a Time Lord Episode 2)


 * 20 - The Mysterious Planet Episode 3 First Broadcast (The Trial of a Time Lord Episode 3)


 * 27 - The Mysterious Planet Episode 4 First Broadcast (The Trial of a Time Lord Episode 4)

October

 * 04 - Mindwarp Episode 1 First Broadcast (The Trial of a Time Lord Episode 5)


 * 11 - Mindwarp Episode 2 First Broadcast (The Trial of a Time Lord Episode 6)


 * 18 - Mindwarp Episode 3 First Broadcast (The Trial of a Time Lord Episode 7)


 * 25 - Mindwarp Episode 4 First Broadcast (The Trial of a Time Lord Episode 8)


 * 28 - Ian Marter, who played companion Harry Sullivan, dies from a diabetes-related heart attack in London.

November

 * 01 - Terror of the Vervoids Episode 1 First Broadcast (The Trial of a Time Lord Episode 9)


 * 08 - Terror of the Vervoids Episode 2 First Broadcast (The Trial of a Time Lord Episode 10)


 * 15 - Terror of the Vervoids Episode 3 First Broadcast (The Trial of a Time Lord Episode 11)


 * 22 - Terror of the Vervoids Episode 4 First Broadcast (The Trial of a Time Lord Episode 12)


 * 29 - The Ultimate Foe Episode 1 First Broadcast (The Trial of a Time Lord Episode 13)

December

 * 06 - The Ultimate Foe Episode 2 First Broadcast (The Trial of a Time Lord Episode 14). Although not widely known at the time, this would be Colin Baker's final appearance in the series.

Unknown date

 * John Flint, who played William des Preaux in "The Crusade" and Captain Urquhart in "Time-Flight," dies.