It was one of the most notorious murders of the 20th Century. On 7 November 1974, nanny Sandra Rivett was bludgeoned to death at the family home of Lord Lucan in London. Lady Lucan, who was also attacked, identified her husband as the assailant, but he disappeared and has never been found. In a fascinating one-off documentary, Lady Lucan gives her first TV interview on the subject in more than 30 years and suggests her husband ‘went mad with the pressure’ after he lost an expensive custody battle for their three children. ‘Everybody who knew him thinks that he committed suicide.’