Robertson has been a regular cast member in series including Channel 4 drama NY-LON, ITV drama Life Begins, BBC Three sitcom How Not to Live Your Life, [Doc Martin (TV series) two episodes, including first ever episode in 2004][ITV comedy drama] and BBC One crime drama The Body Farm. Robertson was also a guest star of the Doctor Who episode, "Blink", which is thought of as one of the best episodes of the series. Robertson has appeared in films, including Alfie, The Disappeared, F, Cockneys vs Zombies, and Hammer of the Gods. Robertson's roles in recent years include the drama series New Tricks, Scott & Bailey, and the docu-drama I Shouldn't Be Alive.