Born in Oxford, Hoare became involved in crime as a teenager and was part of a gang who robbed banks and post offices. By his own admission, they were largely unsuccessful at it and he thus spent much of the 1960s in prison. He once escaped from a high security jail in Liverpool and also served time in Dartmoor prison.
While in prison Hoare took up writing and met Alan Plater, the Z Cars screenwriter who gave tuition to inmates and advised him to write screenplays. Hoare went on to be a successful writer for shows like Minder (writing some 50 episodes), Crown Court and The Sweeney. When Paul Knight was looking for an experienced writer for the first series of London's Burning, he settled on Hoare, who wrote the first episode. Hoare wrote for London's Burning sporadically until 1993 (series 6), when he felt it was becoming too much of a soap opera and pulled out. He died in 2008.