Carnival of Monsters

In retrospect, it seems odd that Doctor Who's anniversary story should be so world-building, so forward-thinking, so unlike the stories of the First and Second, even to a large extent, the Third Doctor – only for the following story to encapsulate, in many regards, intrinsic qualities running throughout the series, and to reflect on them too. But that's what Robert Holmes, and the rest of the production team, managed to do.

It's not just that the Doctor and Jo are back in time and space. They went to the planet of the flea people last year, and the lost city of Atlantis not long after (Jo even got her hair done there). Carnival of Monsters, like my beloved Curse of Peladon, has a cosmic worldview, one that mirrors the unbounded multiplicity of a writer's imagination. Vorg the showman is really Robert Holmes in a false moustache: he can gather who he likes together, make them fight, pick them out of one world and drop them in another. As Jo says, at one point, 'I suppose we're due for monster bit in a minute.'

Like the Doctor (another double of his, in many regards) he's a figure who represents endless invention and mutability. If you can imagine it, the Tardis can take you there, and in this story multiple worlds are conjured up: Inter Minor, 1920s Earth, Drashiggia, and those places only gestured toward – the backwaters and fairgrounds that Vorg and Shirna tap dance in and out of, the Doctor's home planet, where he once ran a political campaign, and the worlds of Ogrons, Cybermen, Prehistoric Earth. In the Miniscope (which is, what – the story, the telly, broadcast media in general?) they can be interwoven.

It's all imagined and woven together so apparently effortlessly, each with its own little narrative, that the viewer really thinks – yes, the Universe really is a big place. And yes, it really is all one thing. Either because we can make it one narrative, or because we can bring it all together and look at it, or because we can travel between them all – these many worlds are all combined in us, our minds, our lives.

Holmes makes the continuity of worlds part of the colour and liveliness of the story. Alien travellers in the far future still use polari – in fact, they sometimes work fairgrounds on Earth (and do we realise they are not Earthmen when we see them?). Grey people called Shallak can fall for the same old cup-and-ball routine you see in old movies. Shirna, the hoofer from beyond the stars, even shares the viewer's POV, entertained by the Doctor's heroics, lifted out of her despondency by the magic of the Tardis dematerialisation at the end.

But it's all one thing in a serious way, too. We are shown that the actions of the audience are not disconnected from the lives of the people they watch, or the governing body that permits the show to run. The personal is political.

This is really a satire on how storytelling runs the world, the unreal representing and sometimes governing the real – from the romantic novel read by a man of the Empire ('Good heavens, a memsahib!' he exclaims, on discovering Jo) which ends disappointingly with a character becoming a missionary, to the machinations of the grey people to make bad news for the President (and play down bad news about the working masses). Power, oppression, pleasure, are all in the same industry.

The Three Doctors has no real story: its pleasure is all in the interplay of Doctors, companions, Omega himself. The problem at the heart of the story is a sad paradox: the freedom of the Time Lords is founded on the suffering of one man. The question is never asked, Is it worth it, or Can we find a compromise? Omega has already gone mad and tried to destroy the universe – the cartooniness of Bob Baker and Dave Martin, which works in its own way – leaves us nowhere to go but a big bang and a scream. In Carnival of Monsters, the oppressive Miniscope is partially transformed into a Tardis, a symbol of liberation. Then it's destroyed – and everything is changed.

Even Vorg becomes temporarily heroic. But like the Doctor, he finishes the story as a man of words rather than status – a vagabond, exactly as the Doctor identifies himself, surviving on his wits.

What's distinctively Doctor Who about this story, is the lightness of touch. It's a complex story, but deftly presented for a general audience: playful rather than self-important. Visually, it's a treat - and it's actually funny. The little guys win the upper hand, and not just by escaping a dimensional compression field. When the Doctor faces the Tribunal at last, he beats them immediately on the strength of his rhetoric – a Doctorish victory more persuasive than the combined Three Doctors managed last story, and a brilliant moment for Jon Pertwee.

Just when you start to think the show has changed completely, or that in leaving UNIT behind it might fall back on old stories, it reminds us why this show means something: invention, reinvention, liberation and alienness.

Can it last...?