On June 14, 1939, the Imperial Japanese Army surrounded and blockaded the British concession over the refusal of the British authorities to hand over to the Japanese six Chinese who had assassinated a locally prominent Japanese collaborator, and had taken refuge in the British concession. For a time, the 1939 crisis appeared likely to cause an Anglo-Japanese war, especially when reports of the maltreatment by the Japanese Army of British subjects wishing to leave or enter the concession appeared in the British press. The crisis ended when the British Prime Minister Neville Chamberlain was advised by the Royal Navy and the Foreign Office that the only way to force the Japanese to lift the blockade was to send the main British battle fleet to Far Eastern waters, and that given the current crisis in Europe that it would be inappropriate to send the British fleet out of European waters, thus leading the British to finally turn over the six Chinese, who were then executed by the Japanese.