Robert was born in Ryton, Durham, to Robert and Grace Pirrie (1901 census). His father Dr Robert Reid Pirrie was a founder of the College of Medicine Gazette and was himself severely wounded in France but survived the war (Medical Gazette Volume XVI, pp. 8 and 96 and Medical Gazette Volume XIX, p. 25).
Robert studied at the College of Medicine from 1910 to 1914, leaving his studies to join the war effort before graduating. Robert features in a number of articles within the student publication of the time, The Medical Gazette. He was a keen sportsman and was a member of Ryton Lawn Tennis Club. He played handicap doubles in the College lawn tennis tournament and was elected to the lawn tennis committee. He was also elected to the hockey committee for 1913-14 and appeared in a students vs professors golf match.
Robert was gazetted as a Second Lieutenant on 24th August 1914 and was attached to 1st Battalion King's Shropshire Light Infantry. Robert was killed in action during an assault on the Hooge trenches on August 10th 1915, aged 21 years old.
Obituary, Medical Gazette Vol XVI, p. 8: ‘Lieutenant Robert B Pirrie, of the Shoropshires, eledest son of Dr Pirrie of Ryton, lost his life on August 10th, while serving with the BEF in France. One of the first of our students to apply for his commission at the outbreak of war, he was gazetted as second lieutenant in August of last year, and was soon ordered to Fance. After being slightly wounded some weeks later, he returned with his accustomed cheerfulness to the firing line, but was fatally wounded on August 10th, in a gallant assault upon the Hooge trenches, in whichhe himself displayed conspicuous bravery. It is now some five years since Pirrie joined the College of Medcine, and during that time, we, who were his contemparies, have had full opportunity of learning his worth. His keen sense of humour, his warm responsive nature, his great love of all true sport, and, above all, his unfailing cheerfulness endeared him to us, and earned for him the wide popularitywhich he enjoyed from the toime of his entrance into the college. No one was keener to do his duty, no one more determined to fight than “young Pirrie” (as we always called him). We knew him as a soldier during his service in the OTC, and we know that he carried with him into the trenches that buoyancy and cheerfulness which is so encouraging and exciting. We, who were his friends and fellow students, join in this tribute to his memory, and offer our deep and sincere sympathy to his bereaved parents. H.B.’