Growing resentment in the labour movement at Lang led to the formation of a breakaway Industrial Labor Party in February 1938 led by MLA for Botany, Robert Heffron. In 1939, the ALP Federal Executive intervened and a unity conference was held in August. Lang's opponents had a comfortable majority and took control of the Executive. In the Parliamentary Party ballot on 5 September 1939, McKell had 13 votes, Lang 12 and Heffron seven. In the next ballot, all of Heffron's votes went to McKell who became Leader of the Opposition.