William Cocks was born into a working-class family in London, England in 1877. He came to Regina in 1904 and apprenticed as a painter. He had some understanding of trade unions from his father, a member of the Steam Engineers Union, and helped organize the painters, carpenters, and bricklayers unions in Regina. Cocks was a member of the Painters Union. On February 9, 1907, a group of trade unionists met in his house and organized the Regina Trades and Labour Council (RTLC). Tom Molloy was the first president, and Cocks the first secretary and later president of the council for two years. Cocks was a socialist, and also a practical and committed trade unionist. His organizing led to 95% of the painters in Regina joining Local 509 by 1909. The painters went on strike in 1910, 1912, 1916, and 1919. He was actively involved in the formation of the Regina Labour Temple in 1912, and held many of the offices, including managing director from 1946 until his death. He was one of four labour candidates for city council in 1914, but all lost. Cocks represented the Dominion Congress of Working Men, and accompanied a delegation of about 100 women who presented a petition on women's suffrage to the provincial legislature in 1915. He was active in the RTLC protests against privately run streetcars in Regina, and caused a vote that initiated a public service. Cocks also helped establish the Workmen's Compensation Board. He died on June 12, 1961.