Appropriately enough, slot number four is filled by the fourth Doctor. Tom Baker's first entry in our 50th list is a fan favourite tale penned by one of the show's most acclaimed writers, the esteemed Robert Holmes...
4. THE TALONS OF WENG-CHIANG (1977) - Six episodes - written by Robert Holmes
"Let the talons of Weng-Chiang... SHRED YOUR FLEEE-AAAA-EEESH!!"
The finale to Doctor Who's 14th series is a wonderfully lurid, Penny Dreadful-inspired piece of drama, where the fog-strewn streets of London are littered with severed limbs and innocents meet a gruesome demise.
'The Talons of Weng-Chiang' features not one but two iconic villains."Slathering, gangrenous vampire" Magnus Greel is in the best Who tradition of a bombastic villain hiding a hideously disfigured face behind a mask, while the knife-wielding 'ventriloquist's dummy' Mr Sin (Deep Roy) is enormously creepy. One can only imagine the bad dreams that must've haunted young Who fans...
But there's more to Holmes's script than pure horror. His six-part story is packed with wit and fantastic one-liners ("What's the name of the tribe here?" "Cockneys.").
He's been gifted too with one of Doctor Who's all-time great casts, with Tom Baker at his absolute peak. There's none of the bored distraction that would pervade some of his later performances - you've never seen a more committed, charming and commanding leading man than Baker in 'Talons'.
Christopher Benjamin and Trevor Baxter meanwhile are marvellous as Henry Gordon Jago - a blustering impressario and (very) amateur detective - and Professor Litefoot - a charming pathologist - respectively.
Given that they're often hailed as Doctor Who's greatest ever 'Holmes-ian' double-act, it's perhaps worth noting that Jago and Litefoot spend most of the story apart, eventually meeting a third of the way through episode five of a six-part tale...
But the distinguished, gentlemanly Litefoot and louche Jago are a classic odd couple with a fantastic repartee. You can see why talk of a spinoff followed the duo for years.
If 'The Talons of Weng-Chiang' has one flaw, it's that Holmes's desire to reflect the UK's 1970s fascination with mysticism and the martial arts led to a rather unfortunate depiction of Asian culture.
At points, you have to chalk up these failings - for example, a white actor in make-up cast in a leading part and placed alongside genuine Asian actors, relegated to non-speaking roles - to 'Talons' being a product of its time.
Elsewhere though, time has been kind to this story in a way that it wasn't to Magnus Greel. The giant rat, often billed as one of this story's major flaws, is really not that bad - certainly compared to other 'failed' Who monsters like the Myrka or the Magma Creature - and the idea of a 10-foot rodent lurking in London's sewers, mauling corpses, is wonderfully horrible.
In fact, thanks to vivid, dynamic direction from Who veteran David Maloney, on a purely visual level, 'Talons' still stands up today - not something one can say of all BBC television of the time.
A sublime blend of science fiction and Gothic Victoriana, loaded with a sense of lingering menace and complete with five storming cliffhangers, 'The Talons of Weng-Chiang' is a high-point in a golden age of Doctor Who and fully deserves its reputation as one of the show's all-time greats.
Are you a fan of 'The Talons of Weng-Chiang'? Does it deserve a place in our Doctor Who top 10? Share your thoughts below!