Records of Prime Ministers of the United Kingdom of . From oldest to youngest: The most recent death of a former Prime Minister was that of Baroness Thatcher (served 1979–90) on 8 April 2013 (aged 87 years, 177 days). Seven Prime Ministers have died in office: Spencer Perceval is the only British Prime Minister to have been assassinated. Sir Robert Peel, Margaret Thatcher and John Major survived assassination attempts in 1843, 1984 and 1991 respectively. Sir Henry Campbell-Bannerman and Bonar Law each resigned during their respective final illnesses. Law died five months after his resignation, but Campbell-Bannerman lived only another 19 days, dying at 10 Downing Street, the
Historical rankings of Prime Ministers of the United Kingdom of 258 academics who specialised in 20th-century British history and/or politics. There were 139 replies to the survey, a return rate of 54%—by far the most extensive survey done so far. The respondents were asked, among other historical questions, to rate all the 20th-century prime ministers (PM) in terms of their success and asking them to assess the key characteristics of successful PMs. Respondents were asked to indicate on a scale of 0 to 10 how successful or unsuccessful they considered each PM to have been in office (with 0 being highly unsuccessful and 10 highly successful). A mean of