Caroline John was a classically trained actress who did some significant and prestigious stage work. However, she is best remembered for one television role which she played for less than a year (and only four serials) - that of Dr. Elizabeth Shaw inDoctor Who (1963). Of the many satellites that have orbited the officialincarnations of 'the Doctor' between 1963 and the present, John was arguably one of thebrightest. Not only was she one of the most attractive of thecompanions but she also stood out for her resourcefulness andintelligence.

The daughter of an actor and a dancer, John was trained at theCentral School of Speech and Drama in London before making her stagedebut with the Royal Court Theatre. She then acted in repertory and hada three-and-a-half year stint with the National Theatre Company underthe auspices of its artistic directorLaurence Olivier, performing in suchplays as "Othello", "The Master Builder" and (as Ophelia) in"Rosencrantz and Guildenstern Are Dead". John joined Lambda in thelate1960s, touring through Italy, Yugoslavia and Romania withD.H. Lawrence'splay "Daughter-in-Law".

Having submitted a glamorous modelling shot of herself to outgoing producersPeter Bryant andDerrick Sherwin, John successfully auditioned for the role of Dr. Liz Shaw and was first featured at the beginning of Season Seven inSpearhead from Space: Episode 1 (1970). Like her immediate predecessor, astrophysicist Zoe Heriot, her character was meant to be super-intelligent (the Brigadier famously describes her as being "an expert on meteorites, with degrees in medicine, physics and a dozen other subjects") who would help the new Doctor (Jon Pertwee) and also shared his moralprinciples. Her strong and independent personality contrasted markedlyfrom the stereotype of the screaming, helpless scatter-brained companions prevalent throughout much of the 20th century series. In a 1987 interview, Johnrevealed that she was on occasion given leeway to ad lib if it helpedto liven up a scene that didn't come off as originally written. However, script editorTerrance Dicks,new producerBarry Letts andJon Pertwee all disliked the character of Liz Shaw, considering her too clever and grown-up to be relatable to the younger members of the audience. They also perceived it to benecessary to more fully explain the'technobabble' to audiences. This required a suitably naïve character to ask the relevant questions. Consequently, John was dropped from the show at the end of the season in favour ofKaty Manning's Jo Grant,a reversion to the show's earlier format.Terrance Dicks later commented that he thought John was actually too good an actress to play a companion to the Doctor. Although he'd written her out of the show,Barry Letts later cast John in his BBC version ofThe Hound of the Baskervilles (1982). John occasionally reprised her role of Liz Shaw for direct-to-videospin-offs, an audio series and for the seminal 1983 reunion specialThe Five Doctors (1983).

Post-Doctor Who (1963), she had aregular spot onHarry Enfield's Television Programme (1990)and guested in such shows asPoirot (1989),Silent Witness (1996) andMidsomer Murders (1997). She also maintained a steady flow oftheatrical engagements and was latterly noted for her solo tour-de-forceas Mildred Asher in "Nightingale", a play written byLynn Redgrave, which ran at the New EndTheatre in London and at the Mark Taper Forum in Los Angeles in 2006.