It wasn’t badged as such, but watching this, it’s inescapably a first anniversary episode. Twelve months ago, a mild curiosity / creepy stalking led Ian and Barbara into a junkyard in London. World’s End returns them to a scrap heap in London, where the TARDIS is incongruously parked in a decaying building site, evoking our first sight of it among a dilapidated pile of junk. The Doctor even comments on how curious people would be to discover a Police Box in such an odd, out of the way place – perhaps a nod back to that very first shot in An Unearthly Child, of a policeman discovering the TARDIS.

This sense of things coming full circle is reinforced by Ian and Barbara’s excitement to be back on Earth – rather ignoring the fact that they haven’t been anywhere else during the last nine weeks. For a moment, this looks like it could be the end of the series. The TARDIS has finally got Ian and Barbara back home. But the audience has already been alerted that things are amiss: in the first example of a Doctor Who cliché, the episode begins with a nameless extra dying and a zoom into a sign that ominously warns ‘It is forbidden to dump bodies into the river.’ We already know there is danger here: and even the contemporary audience would almost certainly have known what given the massive publicity about the return of the Daleks (including the Radio Times front cover).

Terry Nation plays with audience expectations, though, by holding back the Dalek reveal to the end of the episode. And just as the surprise at the end of Planet of the Daleks isn’t that there are Daleks on Spiridon, but that there are invisible Daleks on Spiridon, here the surprise isn’t that there are Daleks on Earth – but that there are Daleks in the River Thames.

Instead, this episode is an exercise in atmosphere and menace. This is London that has already fallen: dead, decaying, deserted. The imagery evokes the Blitz – overgrown bomb sites, semi-demolished buildings, public information posters. It’s a planet almost as dead as Skaro. As in Star Wars, the baddies have already won, and this is about a heroic resistance cell, an It Happened Here style alternative history, not a typical ‘invasion of Earth’ plot of the UNIT era.

The atmosphere is reinforced by the series’ first major film location work – Ian and the Doctor exploring the crumbling docks; Susan and Barbara fleeing across a bombed-out London – and the scenes of the Doctor and Ian exploring the warehouse, which looks like a haunted house. Nation ratchets up the tension by gradually adding new elements – the Doctor’s instinctive unease. Barbara discovering the sinister poster. Both Barbara and Ian discovering dead Robomen at the same moment. The appearance of the resistance fighter who carries Susan away, while another stalks Ian and the Doctor through the warehouse. Finally, the flying saucer and the shambling, Frankenstein’s Monster-like Robomen. All these elements work together to create the sense a distorted, broken future so that Ian’s horror at the idea of discovering what has happened to London, the idea that the answer is too dreadful to contemplate, is thoroughly believable.

As the first part of a self-consciously ‘important’ story – the final adventure in the first production block, the conclusion to twelve months of adventures, the departure of a regular, and the return of the Daleks – World’s End is excellent. It’s easily the biggest episode to date, and one of the best.

Other things I noticed:

• Nation’s script makes an irony of Carole Ann Ford’s departure from the series by having Susan be the character most happy at the idea that the TARDIS crew will stay together: ‘Things have to stay as they are, don’t they? Can’t change.’
• Having paired the Doctor and Barbara / Ian and Susan in Planet of Giants, and then the Doctor and Susan / Ian and Barbara in Dangerous Journey, this episode pairs the Doctor and Ian – who turn into a pair of buddy investigators, and Susan and Barbara, who fret a lot. Whereas in the 1980s the crowded TARDIS caused issues, here the writers seem to actively be testing out different combinations, which is refreshing

Next episode: The Daleks