McClaren, who claims to have been adopted, is Black and also Scottish. This led to a string of racist abuse when he first arrived at Slade prison. Fletch, in reference to his Scottish upbringing, frequently calls him "Jock." Upon arrival, he was an angry young man, and it was left up to Fletcher to calm him down and to curb the abuse he received. A keen football player, he was soon turning out every Saturday afternoon for the inter-wing football matches. He supports Greenock Morton F.C.
Along with Godber and Warren, McClaren is a regular conspirator with Fletch. He is the last of their circle to be released, and Fletcher is seen bidding him farewell in the first episode of Going Straight.