Peter McInnes Syme enlisted at Warwirk Farm in NSW. He was one of three Syme brothers killed in the First World War. John Williams Syme, service number 279, was killed on Gallipoli and his name is recorded on the NSW Government Railways & Tramways First World War Roll of Honour at Central Station, Sydney. Duncan Leslie Syme, service number 4270, was killed in action in the first few days of the Australian attack at Pozieres. His name is recorded on the Auburn War Memorial.
Peter survived for over three years in the Australian Imperial Force, only to die by accident in France after the Armistice. His unit at the time of his death was the Provost Corps. His service record contains the following report:
In company with a French civilian he was out bombing fish - a practice forbidden by army standing orders when presumably a premature explosion of a mills grenade took place resulting in the accidental death of both Syme and his companion.
His surname is spelt as 'Symes' on the Morongla Creek First World War Roll of Honor and the Cowra First World War Memorial Grove.