In the end, the UK's reply to the German move was a diplomatic note, strongly disputing the German claim that the UK was attempting to "encircle" Germany with hostile alliances. The German denunciation and reports of increased German shipbuilding in June 1939 caused by the Z Plan played a significant part in persuading the Chamberlain government of the need to "contain" Germany by building a "Peace front" of states in both Western and Eastern Europe and raised the perception in the Chamberlain government in 1939 that German policies were a threat to the UK.