Peter J. Emerson (born 1943 or 1944) is a political activist in Northern Ireland. Born in Britain, Emerson's father was from County Cork, and his mother from Cheshire. He served as a submariner in the Royal Navy, where he was promoted to first lieutenant. In 1970, he began teaching in Nairobi. He moved to Northern Ireland in 1975, living just off the Shankill Road, where he worked in a youth club. There, he became active in the Ulster Liberal Party and also with Friends of the Earth. In 1980, he and Jennifer Fitzgerald were the leading founders of the Campaign for Nuclear Disarmament in Northern Ireland. In 1984, he attracted attention when he broke into a civil defence bunker and obtained papers which appeared to indicate Soviet military targets in the Republic of Ireland.