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