LONDON -- Prince Harry will become the first British royal to appear in the witness box since the 1890s when he testifies this week at the High Court in London as part of his lawsuit against Mirror Group Newspapers. Here are details of the trial:   What is the court case about?   Harry and more than 100 other people are suing Mirror Group Newspapers (MGN), publisher of the Daily Mirror, the Sunday Mirror and the Sunday People tabloids, accusing them of widespread unlawful activities between 1991 and 2011. Those involved include actors, sports stars, celebrities and people who simply had a connection to high-profile figures. They say the media grou...Keep on reading: Why is Prince Harry giving evidence in court?