Percy was educated at Guy's Hospital, entering in 1910 he qualified L.R.C.P., M.R.C.S. in 1913, and M.B. (Cantab) in 1913. In 1914 he held the appointment of Assistant House Surgeon. On 1st May 1915 he joined the R.A.M.C., and, according to his MIC entered the war in France on the 1st June 1915. Percy served in Gallipoli transporting the wounded on the Hospital Ship "Assaye". He then became attached to the Bershire Yeomany as their medical officer, and with them joined the Western Frontier Force of Egypt in the campaign against Senussi. Percy saw a man drowning at Berrani and jump in, off a rock, into a heavy surf to rescue him. Immediately after a big wave broke over him and he disappeared. His body was found five hours later. He was buried the next day at Berrani, with military honours. He was the son of Frederick and Alice Haycraft Berry of Oxford House, Watford.