Derek Riddell (born 11 January 1967) is a Scottish television and theatre actor.
He is best known for the portrayal of Richard Cawood in the BBC One television series Happy Valley.
He has guest-starred in Doctor Who, Ugly Betty, Silent Witness, Waterloo Road, and Shetland.
[3] After finishing drama school, Riddell was cast in the BBC Scotland production Strathblair and guest-starred in a number of popular TV shows such as Taggart, Casualty and The Bill.
His big break came in the critically acclaimed Channel 4 series The Book Group and the comedy-drama No Angels.