Historical rankings of Prime Ministers of the United Kingdom from his second term only. In 2013, a group of academic staff and students at Royal Holloway, University of London, conducted a postal survey of British Members of Parliament, asking them to evaluate the success of post-war British prime ministers. Some 158 MPs replied to the survey, a response rate of 24%. The respondents included 69 Conservatives, 67 Labour MPs, 14 Liberal Democrats and 8 MPs from other parties. The survey used the same question employed in the 2004 and 2010 University of Leeds studies: MPs were asked how successful or unsuccessful they considered each Prime Minister to have been
Records of Prime Ministers of the United Kingdom have both had immediate successors to die in office. The longest-married Prime Minister was James Callaghan who was married to his wife Audrey for 66 years from July 1938 until her death on 15 March 2005. Three Prime Ministers married while in office, all to second wives: The British Prime Minister widowed the shortest is James Callaghan, who died on 26 March 2005. His wife, Audrey Callaghan, died on 15 March 2005, only 11 days before him. Only two British Prime Ministers have been divorced: Only four British Prime Ministers were bachelors: At least 24 British Prime Ministers were related