Sudan. (Red Cross - Prisoner of War Mail). 1919. Stamp-less envelope addressed to 'Comite International de la Croix Rouge, Agence International des Prisonniers de Guerre, Geneve, Suissse' cancelled by Khartoum/ D date stamp '29th March 19', with 'Opened 3 By Censor/ Sudan' label tied by Port Said transit on reverse and triangular 'Passed By Censor/ 1' hand-stamp on face, boxed 'T' hand-stamp and endorsed '50' in blue crayon for taxation.
Prisoner of War Mail should have been allowed Free Postage.