Harold was born in Norfolk, where his father Henry, was station master at Helhoughton. Henry was married to Rosa and Harold was their fourth child and second son. By the time of the War, the family was living at 40 Parsonage Street, Heaton Norris and Harold was now also working for one of the railway companies. He was employed by the Great Central Railway at the Manchester offices of the Company's Audit Accountant. Nothing else is known of his private life except that a newspaper report of his death noted he was a keen athlete.
Harold was an early volunteer for the army and, like many young middle class men, joined the "Public Schools" Battalion of the Royal Fusiliers. He went overseas with the Battalion in November 1915. There are scant details of the days around when he died. On the 22 August, the Battalion took over a sector of the front line on the right hand edge of High Wood (scene of bloody fighting the month previous). The Battalion's War Diary has no entry for the 23rd. Harold is recorded as having died of wounds yet has no known grave. This suggests that he was wounded but died shortly afterwards, before he could be evacuated miles to the rear to a field hospital. He had probably been injured by an exploding German shell. He will have been buried close to where he died, perhaps only a few hundred yards behind the front line but the location of the grave will have been lost in the subsequent years of fighting.
His older brother, William, is reported to have served with the Army Medical Corps and, also in 1916, undertook a now unknown act of bravery for which he was awarded the Military Medal.
When the War Graves Commission collated its casualty information in the early 1920s, Henry and Rosa Colville were living at 60 High Lever Road, North Kensington, London.