In a departure from the Doctor's first two incarnations, Pertwee's era was influenced by the James Bond film series. He played the character as an active crusader with a penchant for action and fancy clothes, while the character was exiled to Earth by the Time Lords for much of his tenure and serving as the scientific adviser to Brigadier Lethbridge-Stewart and UNIT. He played the Doctor for five seasons from early 1970 to mid-1974, a longer stint than either of his predecessors in the role, although he ultimately appeared in fewer episodes than William Hartnell as the BBC had reduced the production schedule. Pertwee credited his performance as the Doctor with helping him work out exactly who he really was when he was not resorting to comedic disguises or voices: a dapper, technologically oriented man of action. This was because the BBC's Head of Drama, Shaun Sutton, had advised him to act the Doctor as himself: in effect, to "play Jon Pertwee". On 14 April 1971, Pertwee was the subject of Thames Television's "This Is Your Life".