Wallis Simpson became the most hated woman in Britain after King Edward VIII gave up his throne for her and left the country (in a move with echoes in today’s Royal Family). Author and historian Guy Walters asks biographer Anne Sebba how alike Wallis and Meghan Markle really are - and whether we can learn any lessons from the 1936 abdication crisis as the Royal family is once again rocked by the arrival of an American woman.