Jimmy was the leader of a teenage gang in the East End in 1963.
He threatened the First Doctor with a flick-knife, but subsequently stopped and apologised, claiming he was having a bit of a laugh. He was later part of a group of bikers that attacked Susan Foreman on Mayfield Terrace when he was affected by a World War II German weapon that used radio waves to make young people hate and attack anyone who was different to them, but stopped and turned away when Susan dropped her transistor radio. He later followed Susan and Cedric Chivers to a warehouse, and broke down the front gate. Susan used her psychic abilities to slow Jimmy down while the Doctor transmitted a signal that blocked the German weapon. (AUDIO: Hunters of Earth)