Having recently graduated from drama school, landing a role in an ITV primetime drama was a real coup for Ben. He has also starred in an episode of Holby City, Mr Nobody, as well as the play Much Ado About Nothing as Claudio. He was spotted for the role in Primeval while auditioning for the part of Arthur Pendragon in BBC's Merlin.
Since first appearing in Episode 3.1, Mansfield has been a regular in the show's cast, throughout Series 3 to Series 5. He has also featured in spin-off media such as the prequel webisodes before Series 4. More recently, Ben starred in a number of promotions made by Watch for Series 5, including a YouTube game, and also some trailers.