As part of the City of London School OTC he volunteered for foreign service and applied for a commission but was rejected on account of his eyesight. He then trained as a Signaller in the Training Reserve Battalion and was posted to Lovat’s Scouts in November 1917. He was passed fit for foreign service in June 1918 and transferred to the 1st Battalion, The Cameron Highlanders, serving with the Expeditionary Force in France and Flanders from 16th June 1918, being employed as a 1st Class Signaller and was killed in action between Haucourt and Eterpigny on 3 September. A comrade wrote: ‘In the afternoon of the 2nd Sept 1918 his Company (who had earlier attacked at Dury with the Canadians) required a volunteer to go through a heavily shelled section, to take a message to Battalion Headquarters, signalling being impossible. Signaller Pinto volunteered and on his return led his company through heavy shelling to another position; he was slightly wounded but refused to leave ‘the boys’; he subsequently took another message for the company and met his death a little later, while sleeping, completely exhausted, in a shell hole.’ He was buried where he fell although his body was eventually exhumed and reinterred at Dury.

The CWG record shows (Concentration report) that Harold was originally buried somewhere else, but exhumed and reburied at a later date, in war cemeteries. The concentration of cemeteries allowed otherwise unmaintainable graves to be moved into established war grave cemeteries where the Commission could ensure proper commemoration.