Billington was screen-tested for the role of James Bond more than any other actor, auditioning a total of five times and becoming a favored possibility by Broccoli. It is believed by some that he would have received the part had circumstances been different; for example, Moore was considering withdrawing from the franchise in 1981, shortly after the success of The Spy Who Loved Me, due to his age, and Billington was one of the actors tested to replace him. However, Moore instead chose to continue playing Bond, eventually agreeing to three more films after For Your Eyes Only.
Outside of his appearance in The Spy Who Loved Me, Billington was perhaps best known for his role on the British series UFO, where he played Colonel Paul Foster for the show's entire twenty-one episode run, as well as a 1974 spinoff film. Around the same time, he also had a famous role in the historical drama The Onedin Line.
Billlington passed away on 3 June 2005 at the age of 63. His last on-screen appearance was in the early 1990s television program Maigret after a drought of work through the prior decade.