Organizations
The largest of all Polish resistance organizations was the Armia Krajowa (Home Army, AK), loyal to the Polish government in exile in London. The AK was formed in 1942 from within the Union for Armed Combat (Związek Walki Zbrojnej or ZWZ, created in 1939) and incorporated most other Polish resistance groups (except for the communists and some far-right groups). It was the military arm of the Polish Secret State. From 1943 the AK was increasingly in competition with the communist resistance People's Army (Polish Armia Ludowa or AL), backed by the Soviet Union and controlled by the Polish Workers' Party (Polish Polska Partia Robotnicza or PPR). After the fall of France Poles who were not involved in the regular Polish Army in France and combatants who not escaped to Britain created the Polish resistance in France.
"Within the framework of the entire enemy intelligence operations directed against Germany, the intelligence service of the Polish resistance movement assumed major significance. The scope and importance of the operations of the Polish resistance movement, which was ramfied down to the smallest splinter group and brilliantly organized, have been in (various sources) disclosed in connection with carrying out of major police security operations." Heinrich Himmler, 31 December 1942
Read more about this topic: Polish Resistance Movement In World War II