A majority of constituencies are or were (in the case of those abolished) in England, apart from three in Wales and six in Scotland. No prime minister has represented a constituency in Ireland or Northern Ireland.
Douglas-Home was in neither House of Parliament and during an active parliament, briefly for twenty days. He was elected in by-election on 8 November 1963, but did not take his seat until 12 November.
^ abcMembers of the Peerage of Scotland were not automatically permitted to sit in the House of Lords until the passing of the Peerage Act 1963. Up to that point, Scottish peers could only sit in the House of Lords if they were elected as one of the sixteen Representative Peers, or if they held, in addition to their Scottish peerage, an additional title in either the Peerage of Great Britain or the Peerage of the United Kingdom. Following the passing of the Peerage Act, all Scottish peers were given the right to a seat in the House of Lords. This right lasted until the passing of the House of Lords Act 1999.