Jeff Le Rannais, known professionally as Big John Duncan or John Duncan, is best known as the guitarist for the Exploited from their classic lineup of 1980–1983. During that time he played on the albums Punks Not Dead and Troops Of Tomorrow. He also played on many of their single releases, the most famous being "Dead Cities". After quitting the band in 1983, Duncan went on to play in several other bands including the Square Peg and the Blood Uncles, and joined Goodbye Mr.