The military alliance between the United Kingdom and Poland was formalised by the Anglo-Polish Agreement in 1939, with subsequent addenda of 1940 and 1944,[1] for mutual assistance in case of a military invasion from Nazi Germany, as specified in a secret protocol.[2][3][4]
^Paul W. Doerr. 'Frigid but Unprovocative': British Policy towards the USSR from the Nazi-Soviet Pact to the Winter War, 1939. Journal of Contemporary History, Vol. 36, No. 3 (Jul., 2001), pp. 423–439
^Keith Sword. "British Reactions to the Soviet Occupation of Eastern Poland in September 1939". The Slavonic and East European Review, Vol. 69, No. 1 (Jan., 1991), pp. 81–101.
^Weinberg, Gerhard L. (1954). Germany and the Soviet Union. Studies in East European history. Brill Archive. pp. 49–50.