Leonard David McCluskey (born 23 July 1950) is a British trade unionist. He was General Secretary of Unite the Union, the largest affiliate and a major donor to the Labour Party. As a young adult, he spent some years working in the Liverpool Docks for the Mersey Docks and Harbour Company prior to becoming a full-time union official for the Transport and General Workers' Union (T&GWU) in 1979.