Thailand (Imperial Airways). 1933. Illustrated Air Mail envelope addressed to London bearing SG 255, 10s carmine (pair) and SG 273, 15s black and blue tied by Bangkok GPO date stamp '31st Dec 33'.
Inauguration of Imperial Airways 'Singapore - London' return service - Bangkok to London stage '31st December 1933 paying the 35 satang airmail letter rate to Europe.