William Munro Sim was born in Aberdeenshire the son of James and Johan Sim of Lotts in Skerray; he was the husband of Minnie Doris Sim from Southend on Sea. He was a Regular soldier in the Scots Guards at the outbreak of World War Two and may have served in France with the British Expeditionary Force. If he had served with the B.E.F. then he would have been evacuated from Dunkirk in May 1940 when the Royal Navy rescued the British Army from France.

Lance Corporal William Munro Sim was killed when he was caught up in a German air raid on Tuesday the 10 of September 1940 during the London Blitz; he was twenty-five years of age.