LIST OF ACTORS IN DOCTOR WHO
1963 - 1964: Alec Douglas-Home
A bit-part actor who played authority figures and lords - due to the fact he was one, "dabbling" in the arts, as he put it. The role of Dr Who (as it was then) was his first and last major role. In this incarnation, the Doctor was a grand Victorian gentlement scientist, a deliberate anachronism wherever he went and apparent figure of fun who would bring sudden, expected flashes of firmness.
However, Douglas-Home retired the role to return to Lords full-time as Prime Minister Hartnell became increasingly erratic. Needing a way to keep the show going, the BBC decided to reveal the Doctor as an alien who could regenerate himself when wounded - and the Dalek Invasion Of Earth story gave them the opportunity, as a Dalek rose from the Thames and gunned the Doctor down...
1964 - 1970: Harold Wilson
Wilson was deliberately chosen to contrast with his predecessor: younger, a Yorkshire grammar-school lad with a raincoat and pipe (his own), and an engineer out of the modern Sixties. This Doctor would roll his sleeves up, talk 'common sense', and get to work fixing things, and his companions were increasingly younger, 'trendier' figures than the stuffier Ian and Barbara. (Susan, his granddaughter, was phased out in his first story and replaced with Anglo-Indian future rebel Saida)
Behind the scenes, Wilson suffered from depressive moods and this led to clashes with the crew; a few stories had to include moments where the Doctor was "captured" or "lost" to calm things down. This led to Wilson eventually being pushed out, the BBC wanting a more reliable actor around for their budget-saving "Exiled To Earth" stories.
1970 - 1974: Edward Heath
Another lower-middle-class actor, Heath enjoyed the spirit of internationalism from the UNIT setup and pushed for more of it, with his Doctor visiting the nascent EEC on several occasions. With his interests in football and boating, there was a very failed attempt to make him a 'sportsman Doctor' in the first year.
Ratings began to decline in Heath's time in the role, while the supporting cast became more and more prominent: he just wasn't a commanding presence and fellow actors like Nicholas Courtney could do it much better. His intense privacy made it harder for the cast to get to grips with him either. The BBC began to panic and, in 1974, did a thing that seemed sensible maybe if you squint while drunk: they noticed how high the ratings for The Three Doctors had been in early 1973...
1974 - 1976: Harold Wilson
The Doctor was degenerated back into his older form as a reward by the Time Lords. Ratings initially rebounded but then sank again, as by this point Wilson was lacking his old energy and no longer part of the zeitgeist. Ratings fell back down, and the attempt to recentre the show around the Doctor cost most of the Heath-era cast. Once again, the role was recast - as Wilson refused to do the regeneration scene, his successor had to wear his coat from behind and fall over.
Fans have had this Doctor reclassified as "the Fourth Doctor" since the show ended, due to a theory that this was a completely new persona and the Time Lords merely restored his looks.
1976 - 1979: James Callaghan
Initially a popular Doctor, marked with a sunny optimism and a habit of "great debates" about the situation of the episode with his companions - up until behind-the-scenes issues raised their heads again. The BBC was facing financial problems and clashes with the controversial Labour PM Tom Baker, and Callaghan dove in to help the show with suggestions and effort. The nascent fan press reported on this and so whenever anything bad happened, well, Callaghan must've done it.
The nadir was when pressure from Callaghan caused union workers to storm off the set for a week in winter 1978, losing an entire episode. Fanzines and tabloids both had a field day with that one. Wearying of it all, Callaghan agreed to hand in his notice.
1979 - 1990: Margaret Thatcher
Regenerating the Doctor into a woman was seen as a quick attention-getter, and it worked. After a rocky first year, Thatcher's "Auntie Maggie" approach to the role - a warm, maternal, calm figure with steel underneath - struck a chord with children across the nation and helped the show finally crack the American market. Thatcher had once trained as a chemist, and so for the first time the show had an actual scientist working in the role.
The real Thatcher was very much not "Auntie Maggie". The longer she stayed in the role, the more she dominated the show. As long as the ratings were good, the BBC tolerated this even as the writers grew tired of her and various companion actors left - and unlike Callaghan, she gave not a jot what the fanzines said. All this was fine until it wasn't: Thatcher became too settled in the role and forced the show to remain static even as television changed around it. Facing the real possibility that the show could be cancelled, the BBC cornered her in one night and were able to convince her through a mix of threatened resignations and cajoling that it was time to step down.
Unfortunately they didn't have time to get someone else.
1990: John Major
John Major had been part of the "New Comedy" wave, affecting a deliberate and powerful deadpan - his entire schtick was making himself absurdly boring. The BBC, desperate for a replacement, felt Major was popular with certain trendy demographics, he'd do well here, right?
Those demographics were not kiddies, hardcore sci-fi nerds, or Americans. Worse, the end of Thatcher meant the show's writers could go nuts, and did, which created some episodes beloved by fans now but seen as too esoteric for the mainstream at the time.
In the last episode, "Shadows Over Avalon", Major's Doctor finds himself dealing with messages and tricks left behind by his own future self, who will one day end up as 'Merlin' for King Arthur. At the end, this future Doctor is humourously revealed to be played by children's entertainer Alex Johnson - then BoJo the Clown, presenter of Get The Rotters Back! - in full-on court jester activity. "I'm not happy about this," Major says as he looks into the camera.