Under English libel law, a plaintiff must prove only that material is defamatory; the defendant then has to justify it, usually on grounds of truth or fairness.

根据英国诽谤法，原告必须首先证明实质性证据的确是污蔑性的，然后被告才说明是否合理，一般必须秉持真实性或公平性。

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The law concerning Twitter is clear - if you make a defamatory allegation about someone you can be sued for libel.

BBC: Twitter users: A guide to the law

Totalise is now expected to launch a libel action against the person who posted the defamatory messages.

BBC: Websites forced to reveal user identity

In November, Conservative peer Lord McAlpine announced his intention to seek libel damages from Twitter users over incorrect and defamatory insinuations linking him to child sex abuse.

BBC: Twitter users: A guide to the law