Hull was also active in loyalist paramilitarism and around 1970 he helped to establish the Workers ' Committee for the Defence of the Constitution ( WCDC ) , a loyalist trade union of which he was joint leader along with Hugh Petrie of Short Brothers . In February 1971 , he led a march of 9,000 shipyard workers to demand the introduction of internment in the aftermath of the 1971 Scottish soldiers ' killings . Hull 's march was one of the major factors in the resignation of James Chichester-Clark as Prime Minister of Northern Ireland
1971 Scottish soldiers ' killings
1971 Scottish soldiers' killings
Billy Hull