Son of Phillip and Esther Barnett, of 95 Belgrade Road, Stoke Newington, London. He was born on 25 June 1899, in Hackney, the son of Russian-born parents Barnett, a tailor by trade, and Esther Glitzenstein (née Bloomberg). A family argument prompted Glitzenstein to leave home and enlist in the British Army, upon which he assumed the name of Robert Barnett and joined the 1st Battalion, The Prince Consort's Own (Rifle Brigade). Barnett went to the Western Front at the age of 15, below the minimum age of 19 that a soldier was required to be for overseas service. He died on 19 December 1914, in an attack on Ploegsteert Wood, one of three officers and 23 other ranks killed. His death made him one of the youngest soldiers to perish in the war.