In this, his 50th anniversary year, Doctor Who has become a contested figure. The right think he's one of them. The Daily Mail, for example, sees him as an embodiment of "traditional values".
"What finer example of a man - brave, reflective, with a keen sense of heroic duty - is there than Doctor Who?" it writes. And it's true that there are aspects of the character the right are happy with.
The Doctor is an aristocrat from a fantasy super-Britain. His home planet, Gallifrey, is a combination of Eton, Oxbridge and parliament on steroids.
Time Lord parents send their children to the Time Lord academy at the age of eight. Their initiation ceremony is to look into the Time Vortex via the "untempered schism". If they don't go mad, they're enrolled into the universe's most exclusive public school.
It's the oldest civilisation in the universe and they all have upper-class British accents.
In addition The Doctor has been an agent for the CIA (the Celestial Intervention Agency) - a covert Time Lord "Black Ops" division. His mission for the CIA on Skaro, the home planet of the Daleks, triggered the revived series' much-referenced "Time War".
During Jon Pertwee's tenure The Doctor was the scientific adviser to UNIT, a paramilitary organisation whose policy towards alien life was either to shoot at it or blow it up ("Chap with wings - five rounds rapid" shouts Brigadier Lethbridge-Stewart in the 1972 episode "The Daemons").
But the Doctor has many aspects that the right loathe.
He's a refugee from the Time Lord Society who has renounced his patrician status. He's a traveller, a cosmic hobo, living in a mobile home - the Tardis - with no fixed abode. He doesn't use money: "Money? My dear chap, I don't want money. I've got no use for the stuff," he says in one episode.
He's an environmentalist and is anti-oil: "It's about time the people who run this planet of yours realised that to be dependent upon a mineral slime just doesn't make sense."
He's had some interesting friends across time and space including Marco Polo, Vincent van Gogh, and Janis Joplin (she gave him the coat he wore as Doctor No 10). He marched with Mao and played tiddlywinks with Lenin ("A very interesting man") in the sealed train going from Switzerland to Petrograd in 1917.
The fact is, the Doctor is a bit of a lefty. As he tells a crowd of people in 1940s London, "Right, you lot, lots to do; beat the Germans, save the world, don't forget the welfare state."
So whose Doctor Who is he? Ours or theirs? And who cares? Is it a harmless bit of nonsense, bland enough politically for a broad spectrum to feel at ease with? Is it a vehicle for progressive ideas or just escapist pap, part of what Brecht dismissed as the "bourgeois narcotics factory"?
The "Whoniverse" is a place of incredible events but little fundamental change. People wear animal furs at one point in time, frills and ruffs in another and silver space suits in another.
But wherever the Doctor goes there's private ownership, trading (often on a cosmic scale), and forms of production and social relations that are essentially the same as today's.
In the 1977 episode "The Talons of Weng-Chiang" the Doctor tracks down a villain from the future in Victorian London and tells him, "I was in the Filipino army at the final advance on Reykjavik."
Those few words hint at fantastic geo-political convulsions in the far future - but there's still a power crazed dictator around to defeat.
Doctor Who is a good example of the sentiment expressed by the Marxist literary critic Fredric Jameson that "it is easier to imagine the end of the world than to imagine the end of capitalism".
What we get in Doctor Who, despite the progressive politics of individual writers and producers, is capitalism's specific economic and social characteristics presented as the universal laws of social organisation.
In the "End of the World" (2005), for example, the Tardis lands five billion years in the future with the Doctor pitted against the money-grabbing Cassandra. As the Doctor puts it, "Five billion years and it still comes down to money."
But if the series thinks that the rich and powerful will always be with us, at least it's about resisting them and fighting oppression.
As Robert Colvile noted in a Daily Telegraph interview with writer Russell T Davies in 2009, "There's an awful lot of evil bankers and capitalists in your series of Doctor Who."
Doctor Who is about resistance in the here and now and the then and there and that's the best thing we can take from the series.