Innes was born in Stepney, East London and began his career on the stage with the National Theatre of Great Britain under Laurence Olivier. Before that, he trained at Toynbee Hall and evening classes at the London Academy of Music and Dramatic Art (LAMDA), where he was awarded the Shakespeare Cup for excellence. He appeared in the Bernard Kops play "The Dream of Peter Mann" at the Edinburgh Festival and on a tour of Great Britain, directed by Frank Dunlop, under whom he had trained at Toynbee Hall and LAMDA. His final year of study and training was at the Bristol Old Vic School. He worked with Dunlop again in "The Pantomime" at the Bristol Old Vic, before a season at Nottingham Playhouse with Dunlop and John Neville.