The Labour Party governed the United Kingdom of Great Britain and Northern Ireland from 1974 to 1979. During this period, Harold Wilson and James Callaghan were successively appointed as Prime Minister by Queen Elizabeth II. The end of the Callaghan ministry was presaged by the Winter of Discontent, a period of serious industrial discontent. This was followed by the election of Conservative leader Margaret Thatcher in 1979. Historian Kenneth O. Morgan states: The government consisted of three ministries: the third and fourth Wilson ministry, and then the Callaghan ministry.