It's the basis for some of the greatest sci-fi movies of all time -- The Terminator, Back to the Future, Black Knight, just to name a few.

But if you ever find yourself in China wanting to check out what Bill and Ted were up to last week, forget it. Time travelling is banned.

In a bogus move by the Cultural Revolution-loving dudes at China's State Administration for Radio, Film and Television, it has been decided that TV shows that deal with changing history "lack positive thoughts and meaning."

"The time-travel drama is becoming a hot theme for TV and films," it says. "But its content and the exaggerated performance style are questionable."

Some observers claim the real reason behind the ban is that the recent rash of TV time travel dramas focus too much on perceived happier times in the past for its citizens.

No dice, say the administrators.

"Many stories are totally made-up and are made to strain for an effect of novelty," they claim. Time travel plots are made up? Go on with you.

No, it's true: "TWhey casually make up myths, have monstrous and weird plots, use absurd tactics, and even promote feudalism, superstition, fatalism and reincarnation.”

So no Dr Who? Well, maybe: The guidelines only "discourage" such content, rather than outright eliminate it.

But if you want to test out what the words "guidelines" and "discourage" mean when it comes to Chinese administration officials, be our guest. Just make sure you've got a deranged inventor ready to fire up the flux capacitor if it all appears to have gone pear-shaped.

Not that they would know . . .

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