Dan Brown, the American author of the hugely successful novel The Da Vinci Code, was accused on Monday of appropriating the work of two authors of a 1980s non-fiction book “to save the time and effort that independent research would have required”.

Mr Brown made a rare public appearance to hear the start of a ground-breaking copyright infringement claim against Random House, his publisher, at the High Court in London. The publishing company says the claim is “without merit”.