The Armageddon Factor

103 – *The Armageddon Factor*
103 – The Armageddon Factor
Doctor Who serial
Cast
	Doctor Tom Baker – Fourth Doctor;
	Companions Mary Tamm – Romana; John Leeson (Voice of K9);
	Others John Woodvine – The Marshal; Lalla Ward – Princess Astra; Davyd Harries – Shapp; Ian Saynor – Merak; William Squire – The Shadow; Barry Jackson – Drax; Valentine Dyall – The Black Guardian; Ian Liston – 'Hero'; Susan Skipper – 'Heroine'; John Cannon, Harry Fielder – Guards; Iain Armstrong – Technician; Pat Gorman – Pilot;
Production
Directed by	Michael Hayes
Written by	Bob Baker; Dave Martin
Script editor	Anthony Read; Douglas Adams (uncredited)
Produced by	Graham Williams; David Maloney (uncredited)
Executive producer(s)	None
Music by	Dudley Simpson
Production code	5F
Series	Season 16
Running time	6 episodes, 25 minutes each
First broadcast	20 January – 24 February 1979
Chronology
← Preceded by; The Power of Kroll	Followed by →; Destiny of the Daleks
	List of episodes (1963–1989)

The Armageddon Factor is the sixth and final serial of the 16th season of the British science fiction television series Doctor Who, which was first broadcast in six weekly parts on BBC1 from 20 January to 24 February 1979. It was the last to feature Mary Tamm as Romana.

The serial is set on the planets Atrios and Zeos, and another planet in between them. In the serial, a nuclear war between Atrios and Zeos is nearing its end, but with Atrios losing. At the same time, the Shadow (William Squire), a henchman of the Black Guardian (Valentine Dyall), steals the time and space vessel the TARDIS, which contains the first five segments of the powerful Key to Time, and kidnaps Princess Astra of Atrios (Lalla Ward), who is the sixth and final segment.