The contribution focuses on the time between 1948 and 1951, which was seen as one of the most challenging periods in the history of post-war Yugoslavia. In 1948, the Cominform Resolution was issued, expelling the Communist Party of Yugoslavia from Cominform. In Yugoslavia, the expectation that the Soviet Union and its satellite states would attempt a military intervention caused many administrative, organisational, and doctrine changes, as the Yugoslav Army kept responding to the strategic developments in the military-political position of Yugoslavia. Due to this crisis, the experience from the National Liberation War was studied yet again, while Yugoslavia was forced to establish closer connections with the Western countries. The military and political events in Yugoslavia were also closely followed by the British government, which kept receiving reports on the state of the Yugoslav armed forces from the British military attaché. The British estimates of the Yugoslav Army’s defence capabilities in the case of a potential Soviet military intervention and how the British could provide military aid to the Yugoslav side in such circumstances are particularly interesting.