Harold Horton was born in Birmingham, Warwickshire, on 25 November 1919, the son of Henry Francis Horton (a letter sorter for the GPO) and Ida Horton (née Turner). At the time of the 1921 Census the family were living at 41, Parker Street, Edgbaston and there were two older half-brothers.

When the 1939 Register was taken in September 1939 Harold’s parents had moved to 147, Lode Lane, Solihull, Warwickshire but neither Harold Graham Horton nor his half-brothers were at home. It is not known when Harold Horton joined the Royal Navy or submarines but by September 1943 he was a Leading Stoker serving in HMS TROOPER.

HMS TROOPER left Beirut in the Lebanon on 26 September 1943 for a patrol in the Aegean Sea in the Leros area during which a special operation was to be carried out. The submarine failed to arrive back at Beirut on 17 October as planned, was reported as overdue and assumed to have been lost with all hands, probably by striking a German mine to the east of Leros.

However, on 6 October 2024 it was announced that a Greek search team had located the wreck of HMS TROOPER in 253 meters of water to the north of Donoussa Island in the Aegean which was in the area HMS TROOPER had been ordered to patrol between 6 and 9 October 1943.

Harold Horton, who was unmarried, is commemorated on the Chatham Naval Memorial on Panel 71, Column 3 and on a family headstone in the Lodge Hill Cemetery and Crematorium in Plot No. B13 380.