William McQuiston, also known as "Twister", is an Ulster loyalist, who was a high-ranking member of the Ulster Defence Association (UDA). Leader of the organisation's A Company, Highfield, West Belfast Brigade, McQuiston spent more than 12 years in HM Prison Maze outside Lisburn for possession of weapons. He is now a community activist, often working with former members of the Provisional Irish Republican Army (IRA) in West Belfast's troubled interface areas where adjoining loyalist and republican communities occasionally clash.