WW2 - POLISH FORCES IN EXILE IN LONDON. POLISH MILITARY POST - thirteen (13) franking and propaganda stamps, cancelled with the seal of the POLISH FORCES in G.B., war scenes of Poles engaged in combat with the allied forces (parachutists, aviators, sailors, tankers... legends in Polish and English. These stamps were issued in 1942, those surrounded by a black frame (mourning stamps) were issued in 1943 to pay tribute to General SIKORSKI, leader of the Free Polish Forces and Prime Minister of the Polish Government in exile in Great Britain from 1939 to 1943, who died on 4 July 1943 in the crash of his B 24 plane as it was returning to London from Gibraltar.