Inspirations - The Armageddon Factor

The Armageddon Factor saw the programme at a point of some change. Though it wasn't known at the time, this was to be the last six part story to be broadcast, and the final collaboration on Doctor Who for writers Bob Baker and Dave Martin, who had been regular contributors since The Claws of Axos back in 1971. Anthony Read stepped down as Script Editor, and Mary Tamm decided that she would not be talked into staying on for another season as Romana. John Leeson also decided to move on from voicing K9.
In terms of starts, this story saw the first appearance of Lalla Ward, who would go on to play the second incarnation of Romana, and new Script Editor Douglas Adams arrived to oversee the final section of the story, which would wrap up the whole Key to Time saga.
We were also introduced to the Black Guardian, as portrayed by Valentine Dyall, who would return for a trilogy of stories during the 20th anniversary season.
Of course, there was one further six part story planned for the conclusion of Season 17, but Shada was cancelled part way through the studio recording period and was never completed or broadcast.
John Nathan-Turner then took over as producer and realised that he could get seven stories per season by dispensing with the six parter - which meant seven "first nights" with their attendant publicity.
It could be argued that there was one further equivalent to a six part story further down the line - once the series had moved to 45 minute episodes. This was the three part The Two Doctors.

For their inspiration for The Armageddon Factor, Baker & Martin looked to the Second World War and the Cold War. The story sees twin planets Atrios and Zeos in the midst of a decades long war. They are basically the Super Powers America and the USSR, or Britain and Germany in WWII.
The leader of the Atrian armed forces, the Marshal, gives Churchillian speeches to rouse his people, and makes propaganda use of Princess Astra of the Atrian royal family. King George VI and his wife and daughters were often employed to help raise morale in Britain, especially during the Blitz when they would go walkabout in the recently bombed parts of London.
The story opens with a bit of propaganda, which leaves the audience thinking they are going to see a badly performed story with dodgy CSO work. It's actually a programme within the programme - a piece of romantic morale boosting, which contains the immortal line "Young men, out there, are dying for it...". The Hero is referring to the war, naturally.
For research, Baker & Martin visited a Cold War bunker near Bath, which inspired the Marshal's War Room scenes. For a war story, we never actually see any of the conflict - it's all done with computer displays and radio communications.
It transpires that there is a third force at work, manipulating both sides behind the scenes - the Shadow. This isn't a new thing for the series. Indeed, the very first Dalek story was originally to have featured the arrival of an alien race in the closing episode, come to claim responsibility for starting the war between the Daleks and the Thals. They would have reconciled the two Skarosian races, agreeing to help rebuild their planet, and it is unlikely that the series would have lasted more than a couple of seasons had this early draft been the one which was made and broadcast.
Later we had the Earth and Draconian empires being manipulated into going to war with each other, this time by the Master and his Ogron allies, who were in the pay of the Daleks. They planned to invade the galaxy once the two empires had weakened themselves through the manufactured conflict.

Once he is on the Shadow's "planet of evil" - which actually looks like a space station but is frequently referred to as a planet - the Doctor encounters another Time Lord by the name of Drax. This character actually originated in an unused version of the writers' The Hand of Fear scripts. This was when that story was a six parter, intended to conclude the 13th Season. The character was described as having a mop of curly ginger hair, but the director - Michael Hayes - must not have read that bit when he cast the balding Barry Jackson. Drax speaks with a cockney accent, having spent some time in HMP Brixton after being caught stealing parts for his TARDIS.
Drax was employed by the Shadow to build a computer called Mentalis, which runs the Zeon armed forces - the original population of the planet having been wiped out years ago (presumably by the Shadow rather than by the Atrians, though this is never specified on screen). If Mentalis is destroyed, it will trigger the Armageddon of the title, wiping out this entire sector of space.
Another long running war is referenced when Drax uses the dimensional control from his TARDIS to shrink himself and the Doctor. They then hitch a ride inside K9 to get into the Shadow's lair undetected - using K9 as a Trojan Horse. The Doctor fails to mention that he gave Odysseus that idea in the first place.

The sixth segment of the Key to Time proves to be Princess Astra - the sixth child of the sixth dynasty of the sixth house of Atrios. Baker and Martin were originally going to have the segment the Shadow's shadow. When it came to discussing the story arc with Anthony Read, it was explained to them that the Black and White Guardians were gong to be two aspects of the same character, but it was then decided to make the relationship between the two more vague.
Baker and Martin also wanted to have it made more explicit that the Shadow wasn't the only agent of the Black Guardian whom the Doctor and Romana had encountered throughout the season. As it is, only Cesair of Diplos, in The Stones of Blood, might just have been an agent, but even that isn't clear.
For the second year running, Producer Graham Williams spent a frantic few days trying to convince his leading lady to stay on the show, and for the second year running he failed. Tamm was unhappy that the character had not turned out in the way originally promised her when she accepted the role, and felt there was little more she could do with it. She half-jokingly suggested Lalla Ward as her replacement one lunch time, having seen how well Tom Baker got on with her, and was surprised to later hear that the idea was taken seriously. Tamm became the third companion to leave without any farewell scene - the first being Jackie Lane's Dodo, who disappeared halfway through The War Machines, and the second being Caroline John whose Liz Shaw vanishes between seasons 7 and 8.
Companion departures are obviously a much bigger deal these days - interminably so in the case of Clara Oswald.

The general consensus is that The Armageddon Factor is an unsatisfying conclusion to what had been a season-long story. The Black Guardian turns up at the very last minute, posing as his White counterpart, but is quickly seen through by the Doctor. The Key is then broken up and re-scattered through Time and Space, never having really been seen to do what it was supposed to do - namely restoring universal balance. Astra is reconstituted - implying that all the other segments have gone back to where the Doctor and Romana found them. This is a problem, if true, as their whereabouts are now known. The final TARDIS scenes were the first to be overseen by Douglas Adams as he took over his new role.
Graham Williams had come to the job intending to do a season-long story arc, but after Season 16 he decided it was a case of "never again". The arc had meant that he did not have the freedom to swap stories around and respond easily to production problems. By way of signifying this, the Doctor installs a new piece of equipment to the TARDIS console - the Randomiser. This will mean that he has no control over where they will land - hoping that the Black Guardian won't know where he has gone either. As it is, if you've read my post on the Randomiser back when I reviewed the Season 17 stories, the device was continually over-ridden - or just plain ignored by the writers of that season.
Next time: Douglas Adams introduces a lot more humour into the series, which is welcomed by Tom Baker, but not so much by Terry Nation...