Frazer Hines
Hines' "Doctor Who" debut came in 1966, when he was cast to play the part of Jamie McCrimmon, the companion of the Second Doctor (played by Patrick Troughton). Originally intended as a one-off guest character, Jamie joined the regular cast and appeared in the series from 1966 to 1969. Hines reprised the role in a cameo in the 20th anniversary serial "The Five Doctors" (1983) and as a guest star in "The Two Doctors" (1985). Hines would appear in 117 episodes of "Doctor Who" in all—more than any other "companion" actor in the history of the series. The only actors appearing in more episodes are those who played the first four Doctors. Many of the episodes featuring Jamie no longer exist in the BBC's collection.
David Troughton
On television, his roles have included guest appearances in "Survivors", "The Life and Times of David Lloyd George", "Rab C. Nesbitt" and "Doctor Who", first as an extra in "The Enemy of the World" (1967–1968), then as a soldier in "The War Games" (1969), both times alongside his father who played the Second Doctor, and in a considerably larger role as King Peladon in "The Curse of Peladon" (1972); as Sergeant Pritchard in the BBC television sitcom "Hi-de-Hi!" series 2 episode 12 and as Brinsley in the episode Sons and Lovers in "Sorry!". In the television adaptation of Alan Ayckbourn's trilogy "The Norman Conquests" (1977), Troughton appeared as Tom, the veterinarian; later he was the physician Bob Buzzard in the two series of "A Very Peculiar Practice" (1986 and 1988). Also in 1986, he appeared as himself in the ITV children's TV show "Rainbow", appearing as the guest storyteller in the episode "What's Wrong With Bungle". He was Uncle Sid in "Cider with Rosie" (1998) and also appeared in the role of Sir Arthur Wellesley (the Duke of Wellington) in the first two episodes of "Sharpe". He appeared as an alien hunter in the comedy/drama mini-series "Ted and Alice" in 2002, and in 2005 he also played Sgt. Clive Harvey, side-kick to the title character of the ITV detective show "Jericho". He appeared in an episode of "Agatha Christie's Poirot" in 1993 ("The Yellow Iris"), and in two separate episodes of "Midsomer Murders", in 1998 and 2007, playing two separate characters. He appeared in the first episode of the TV adaptation of "The Last Detective" in which his "A Very Peculiar Practice" co-star Peter Davison (also ex-"Doctor Who") starred.