William Robertson died as a Prisoner of War. His service record states that, according to Red Cross reports, that he died at a POW camp in Germany.

There is some doubt to the story that the POW's Clarke and Robertson died in Germany. Douai is not a "concentration" cemetery, i.e. remains were not bought in from other cemeteries for re-burial. From the CWGC's cemetery description "Douai Communal Cemetery was used during the occupation years of 1914-18 by the Germans for prisoners of war and British, French, Russian, Rumanian and Italian soldiers, as well as German soldiers were buried in it."  It is possible that the Red Cross reports were not correct as to the place of death of these men, and that they were taken, wounded, from the battlefield by the Germans and died at Douai.