Is the Prevention of Terrorism Act a panicked "one off" reaction to the threat from Al Qaeda? Or is something else going on? An argument can be made that Britain left the path of civil rights some time ago. John Major's government, keen to be seen to "do something" about crime, abolished the "right to silence," for example. Why? If everyone is innocent until proven guilty, why should a defendant's refusal to cooperate be deemed to imply guilt? I am not arguing (for the moment) that freedom is indivisible. But the "presumption of innocence" is really important. John Major's government (Home Secretary, one Michael Howard) may have begun something bad by chipping away at a fundamental right.
Or perhaps it began sooner? Margaret Thatcher (instinctively a real individualist in most respects) found it so offensive that IRA/Sinn Fein leaders should be interviewed that she contrived to have them banned. They could be filmed, but their words could not be broadcast. It's hard to have much sympathy for them, but the problem about freedom is one can't pick and choose. The freedoms we need to protect the hardest are those of the people we actively dislike.