Before the outbreak of World War II, the Polish government signed an agreement with the Royal Air Force.

According to the appendix to the Polish-British Alliance, in the event of war with Germany, two Polish bomber squadrons were to be created on British soil.

As there was a large number of Polish airmen, often with experience in combat against German forces in Poland and France, further bomber squadrons were created by 24 July.

In 1941 while the unit was equipped with Wellingtons and flying from Hemswell on "gardening" (mining) operations, the squadron's Intelligence Officer was Michael Bentine, later to become well-known as an entertainer.

During the war the squadron took part in most of the notable air offensives in Europe, including attacks on the Germany Kriegsmarine preparing for Operation Sea Lion, also ships such as the German battleship Gneisenau docked in Brest, France, other naval facilities in Wilhelmshaven and its U-boat facilities in Saint-Nazaire, Millennium Offensive on large bombing raids on Cologne, bombing raids on V-weapons sites, D-Day, in support of crossing the Rhine, the Battle of the Ruhr, the bombing of Hamburg, and the Battle of Berlin.