Should governments be able to block websites?

[artistry]

There are freedom of speech rights in the US, are there not the same rights in the UK? If there are no issues regarding national security or such, the government should not block the release of information to the public. Regarding the bomb making instructions, it's easier to research on the internet, but if someone wanted instructions, wouldn't they be able to visit a public library and obtain the same information? There would not be any way to control a person, bent on destructive behavior. The law would have to be one step ahead of the potential perpetrator.