Sir was a prefix, placed in front of the recipient's given name, used to denote knights. (TV: The Crusade [+]Loading...["The Crusade (TV story)"])
Sir Andrew Williams's P.R.O.B.E. data profile, which listed his title as "Sir". (HOMEVID: A Message From Sir Andrew [+]Loading...["A Message From Sir Andrew (home video)"])
It was considered a title. Sir Andrew Williams's P.R.O.B.E. data profile listed it as such alongside his first name, surname, species and planet. (HOMEVID: A Message From Sir Andrew [+]Loading...["A Message From Sir Andrew (home video)"])