He is the only actor to have worked alongside all the Doctors bar Christopher Eccleston and David Tennant in one form or another.
After Tom Baker, he was the second longest running cast member of "Doctor Who".
He made his first appearance on "Doctor Who" in 1965 and his last in 1989.
His father was a British diplomat assigned to Egypt.
During the 1950s, he was a private in the British Army.
He appeared with Jean Marsh in both his first and last "Doctor Who" appearances.
Along with Patrick Troughton, he is one of only two actors to play the same character (Brigadier Alistair Gordon Lethbridge-Stewart) in "Doctor Who" in the 1960s, 1970s and 1980s.
He was born one day before his fellow "Doctor Who" star Jacqueline Hill.
He was a close friend of his Doctor Who co-star Jon Pertwee for many years.