After the loss at the Battle of Tampere on 6 April 1918, Kullervo Manner was given dictatorial powers and Wesley was dismissed. Before the socialist faction fell in late April, Wesley fled to Soviet Russia. He moved to East Karelia and joined the Murmansk Legion, which was a British-organized unit comprising Finnish Red Guard fighters who had fled to Russia. During the Allied North Russia Intervention, Wesley served as an interpreter and an intelligence officer and ranked as a British Navy lieutenant.