The story was first proposed by Script Editor Terrence Dicks during the writing of Bon Baker and Dave Martin’s story ‘The Mutants, for series 9. Dicks was aware that the tenth anniversary needed some sort of story to look back at the past and he wanted to bring all three Doctor Who’s together.

William Hartnell had retired from acting shortly after leaving Doctor Who in 1966 at the end of ‘The Tenth Planet’. He had been suffering from arteriosclerosis, or hardening of the arteries, which caused the actor some memory loss and considerable frailty.

Patrick Troughton had left Doctor Who after completing the ‘War Games’, a story written by Terrence Dicks to finish the sixth season in 1969. However, he was a very busy man, and so recording of the episodes where put back from the end of series nine’s shooting scheduled and moved to be the third story filmed, although it would be transmitted first.

The script went through several drafts, starting out set in a limbo dimension beyond the event horizon of a black hole. During the various stages of re-writes, Heather Hartnell, the wife of William Hartnell, contacted producer Barry Letts. She was concerned about the amount of work he would have to do in the story. Terrence Dicks then reworked the scripts to cut down the First Doctor’s appearance to being only on the TARDIS scanner in episodes one, two and three, and then joining forces with the other two to for the final battle.

Even this proved to be too much and William Hartnell’s role was reduced further to only appearing on a monitor for the whole story. All of these segments would be pre-filmed, filming taking place on Monday 6^th November 1972 at Ealing Film Studio.

The scenes where recorded one by one, and the script was read off a large cue cards, positioned out of shot.

This was to William Hartnell’s last piece of acting work, in a career that had spanned fifty years. He died peacefully in his sleep on 23^rd April 1975.

Patrick and Jon had never worked with each other before and their different styles of acting clashed on the set. Jon liked to deliver the lines word perfect, taking his cues off the other actors. Patrick liked to improvise more. Seeing that it was causing Jon a problem, Patrick endeavoured to learn the script exactly and seen the two actors where getting along famously. Their friendship lasted until Patrick Troughton’s death in 1987, shortly after his last appearance in Doctor who in the ‘Two Doctors’.

The story contains many references to past stories. – The second Doctor met the Brigadier in ‘The Wed Of Fear’ (1968). – The Doctor met him again in the Invasion, when he learned that he had formed UNIT (1968). The Time Lords eventually sentenced the Second Doctor to exile and he arrived on Earth in a meteor shower, ‘Spearhead From Space’ (1970). It seems fitting that this story will see the end of the Doctor’s exile, as he is forgiven for his past misdemeanours, and he will be allowed to roam the Universe again.

Omega will return to Doctor Who in the Fifth Doctor story, starring Peter Davison as the Doctor, in the series twenty story ‘Arc Of Infinity’ (1983). The story was a direct follow on from this story, and contained many references to the past, and this story.

Adapted from the inlay cover to the UK VHS release of the story (BBCV7364).

Location work for the story was conducted at

1. Summerfield Bungalow, Springwell Lane, Rickmansworth, Hertfordshire
2. Springwell Quarry, Springwell Lane, Rickmansworth, Hertfordshire
3. Springwell Reservoir, Springwell Lane, Rickmansworth, Hertfordshire
4. Halings House, Halings Lane, off Tilehouse Lane, Denham Green, Buckinghamshire.

Episode 1’s location was shot on 7, 9 and 10 November 1972.
Episode 2’s location was shot on 7, 8 and 10 November 1972.
Episode 3’s location was shot on 9 November 1972.
Episode 4’s location was shot on 7 and 9 November 1972.

Studio recording was conducted in late November and early December 1972.
Final editing and adding of musical soundtrack conducted late December 1972.

BBCi Episode Guide
Doctor Who Reference Guide
Doctor Who's Tragical History Tour (Photographs)
Doctor Who's Tragical History Tour (Screen Captures)