The solution to protecting the London Underground from terrorist suicide bombers can be summed up in one word: Daleks. One Dalek per tube platform, behind a door at the end. Fit them with cameras and remote controls and run them from Ken Livingstone's office. Any sign of terrorism on the platform? Whoosh! The doors open and the Dalek comes out, shrieking "exterminate!" in a demented rasp reminiscent of Michael Howard during his tenure as Home Secretary, only less merciful.

The British are trained from birth to know the two tactics for surviving a Dalek attack; run up the stairs (or escalator), or hide behind the sofa. There are no sofas in the underground, but there are plenty of escalators. Switch them to run upwards when the Dalek is out, and you can clear a platform in seconds.

Suicide bombers are by definition Un-British, and will therefore be unable to pass a citizenship test, much less deal with the Menace from Skaro.

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