The censoring of facts is rarely done in the UK for prudish reasons (such as with, e.g., porn), but is usually done for some kind of strategic/tactical reason.
The Official Secrets Act outlaws leaking government documents in any medium, even if the public would benefit from the secret knowledge. This prevented, e.g., a memo outlining American plans to bomb the Arab TV station Al Jazeera.
Some military info is censored(?)
On the other hand, what with the UK not actually being a completely authoritarian state, this rule -- like most other censorship rules -- is only partially enforced. see, for example, , where state secrets were published apparently for no greater reason than 'because we can'.
I think the distribution of certain facts by unauthorised third parties is censored if they constitute copyrighted information, tho lists of data etc are generally exempt from censorship/copyright/etc.
Instructions in how to commit a crime are illegal (?)
- British Board of Film Classification censors 'imitable techniques'
Children are censored somewhat from facts pertaining to sex outside of an official educational setting. e.g., no few refferences are made to sex in children's stories, shows, etc, unless the book/show is specifically sex-ed related, tho to my knowledge there are no laws forbidding the dessimation of factual sexual knowledge to childeren.
Information on accused criminals and victims are censored to protect the accused and guilty
Libel and Slander
If the facts pertain to a certain person/organisation and could damage their reputation, then they must be substatiatable upon request at fear of punishment. Unlike other laws in the UK, libel and slander are 'strictly liable'; that is, you have no presumption of innocence, you have a presumption of guilt and must prove the factual accuracy of your statements to avoid punishment.