Frank Cousins, General Secretary of the TGWU, served as Minister of Technology from 1964 to 1966, and during this period, Nicholas became Acting General Secretary, also serving on the General Council of the Trades Union Congress. In 1967, he returned to the Labour NEC. He took early retirement from the union in 1968 to become General Secretary of the Labour Party, having been offered the post by Harold Wilson after several other candidates refused the position.[1]
Nicholas was criticised after Labour lost the 1970 general election, and he stood down in 1972.[1]