Can you name someone who left a particular sitcom before it became "popular"? They need to be in more than one episode.
Dad's Army seem to have a number of people who were only in the first series:
Caroline Dowdeswell - played Janet King, a clerk at the bank.
E V H Emmett - played the voice at the beginning.
Martin Wyldeck - played Major Regan, who was a bit of an enemy for troop.
I seem to recall with Dad's Army that in the first episode there was another prominent platoon member, a pampered middle class middle management type, I can't recall the name of the character or the actor (I think he looked a bit like Robert Dorning but wasn't), but he was gone by episode two perhaps considered too close to either Mainwaring or Wilson; only one episode but given what the character could have become I think he warrants fifth Beatle status.
Harry Enfield once said he had to leave Men Behaving Badly for it to become a success; Last of the Sumer Wine arguably only became a success after Michael Bates departure, and how about George Layton in It Ain't Half Hot Mum, though I suppose that was pretty successful from the off (though wasn't Dad's Army?) Similarly with Yes Minister which dispensed with the Frank Wiesel character after one series.
Quote: Tursiops @ April 24 2012, 4:07 PM BSTHarry Enfield once said he had to leave Men Behaving Badly for it to become a success;
Being crap didn't help did it 
Can't think of any sitcom examples but Chris Langham in Not The Nine O'Clock News springs to mind.
I've remembered.
There is a famous example which became a bit of a cliche.
Chuck Cunningham brother of Ritchie.
Went upstairs in Season 2 and was never seen or mentioned again.
Quote: Tursiops @ April 24 2012, 4:07 PM BSTI seem to recall with Dad's Army that in the first episode there was another prominent platoon member, a pampered middle class middle management type, I can't recall the name of the character or the actor (I think he looked a bit like Robert Dorning but wasn't), but he was gone by episode two perhaps considered too close to either Mainwaring or Wilson; only one episode but given what the character could have become I think he warrants fifth Beatle status.
Harry Enfield once said he had to leave Men Behaving Badly for it to become a success; Last of the Sumer Wine arguably only became a success after Michael Bates departure, and how about George Layton in It Ain't Half Hot Mum, though I suppose that was pretty successful from the off (though wasn't Dad's Army?) Similarly with Yes Minister which dispensed with the Frank Wiesel character after one series.
The Dad's Army character was Bracewell, played by John Ringham.
There are also people that leave sitcoms/whatever early because they become successful elsewhere, Anne-Marie Duff as Fiona Gallagher in Shameless and Sarah Hadland in Horrible Histories
It's difficult to work out when Last of the Summer Wine became popular. Obviously it needs Compo, but there are regular characters/actors people forget, such as Wally Batty (Joe Gladwin) and Sid (John Comer).
Megan Dodds in Not Going Out perhaps? Not sure when NGO started to get popular.
Interesting topic.
Last of the Summer Wine definitely - Foggy is the man; Blamire I would argue was pretty much forgotten until videocassettes, DVD, increasingly high profile of TV history etc.
The show only really became a smash with Series 5, shown during the 1979 ITV strike, and therefore watched by far more than previously (it was also pre-watershed for the first time). It never looked back.
Michael Bentine in The Goon Show! How can I forget that? It ran for about 10 years, but he was associated with it despite only being in the first series!
There are sometimes cast changes from pilot to series (not sure if we should count this under this topic or not). I know that Lisa Kudrow was Roz in the pilot of Frasier.
Quote: Tim Azure @ April 26 2012, 7:21 PM BSTMichael Bentine in The Goon Show! How can I forget that? It ran for about 10 years, but he was associated with it despite only being in the first series!
The first two series, I think, not having Wilmut at hand.
Quote: Kenneth @ April 27 2012, 6:12 PM BSTThe first two series, I think, not having Wilmut at hand.
I didn't realise Michael Bentine was in two series and that he was a regular all that time.
Robert Conway in Taxi is a classic examaple, and there were a few characters in the first series of M*A*S*H, Spearchucker and the houseboy spring to mind.
Jeff Conaway?
Randall Carver is a better example in Taxi.
Quote: Steve Sunshine @ April 27 2012, 11:40 PM BSTJeff Conaway?
That's the fella.
Randall Carver is a better example in Taxi.
Who he?