Stephen Lamport, the Prince of Wales's private secretary, demanded that the newspaper's editor, Piers Morgan, apologise to Prince Harry for the third "trivial and intrusive" story about him since he started at Eton two months ago.
In response Mr Morgan accused St James's Palace of being involved in an attempt to censor the press. The newspaper had carried a front page story stating that Prince Harry has had an accident, but they were not allowed to report it. It said the attempts by the Palace to suppress the story was "a farce".
Mr Lamport said in his letter: "I can assure you there is no public interest whatever in the very minor bruising which Harry sustained - of the kind which can happen to any children up and down the country on the playing field ... Yet you sensationalise them to an extent which makes it very difficult for Prince Harry to have a normal life at school." The Mirror carried the letter on its front page with key sections blacked out.
Mr Morgan replied to Mr Lamport: "How do you think William and Harry felt about the material contained in Penny Junor's book about their mother- and fed to them by your own staff? The truth is that you wish to control everything the media writes about the people you work for."