What is the name of the paternal grandfather of Alexander Macmillan ?
Alexander Macmillan, 2nd Earl of Stockton:  He is the first son of the late Conservative politician Maurice Macmillan and the first grandson of former prime minister Harold Macmillan. Maurice Macmillan:  He was the only son of Harold Macmillan, who previously served as Prime Minister of the United Kingdom.
Harold Macmillan