Telford has appeared in several series, including as Eva Braun in Hitler: The Rise of Evil, as Anna Klein in Criminal Justice, as Marianne Swift, a freelance Daily Mail Journalist in The Thick of It, as an undercover police officer in Ashes to Ashes, as Sarah, a Doctor and Dr. Watson's romantic interest, in Sherlock. In 2013, she played Claire Sutton, special adviser to Jim Hacker in Yes, Prime Minister, the revival of the political comedy, and Michelle Paradise in the ITV drama Love & Marriage.