Vicki had joined the Doctor, Ian and Barbara in the story The Rescue, shown at the start of the year, filling the void left by the departure of the Doctor's granddaughter Susan. Together the crew had voyaged through space and time, from ancient Rome to medieval England, from mysterious Vortis to the deserts of Aridius and from the barren planet Xeros to the jungles of Mechanus. The four had fled from Daleks and Drahvins, battled Zarbi and Mechanoids and befriended Kings and peasants.
In the end it was love that saw Vicki leave the Doctor in the story The Myth Makers. When the TARDIS landed near Troy, she fell in love with Troilus, the son of the trojan King Priam, who changed her name to Cressida, She left the Doctor to forge a life with the trojan prince, thus earning a place in history and in time, becoming a character in a Shakespearian tragedy, based on events taking place some 3000 years before her birth.
While Vicki's departure was a concious decision for the character, it was a shock to the actor portraying her. Maureen O'Brien had returned from the summer break to attend rehearsals for the new series at the North Kensington Community centre, only to discover the character was being dropped at the end of the first story. Believing that O'Brien wished to leave the series, new producer John Wiles had decided to replace the character of Vicki, with a new character, Katarina, who would be introduced towards the end of the story. However nobody had thought to tell O'Brien.
We went off on our six week break, and when I came back I expected to find the next four scripts waiting for me, And there weren't any scripts. If they had offered me another contract I might have been torn, because even £50 a week was a lot of money. I suppose I was angry because I had gone on holiday and I would rather have been looking for work.Script editor Donald Tosh took up the story
The writing out of Vicki is one of the things I really regret about my time in Doctor Who, because it was unfortunately so badly handled. I understood that Maureen wanted to go. We got to the first read through and Maureen arrives absolutely furious, because nobody had told her. It was deeply deeply embarrassingLike many departing Doctor Who companions O'Brien found that staring in a weekly TV series, watched by up to 13 million viewers each week, was no guarantee of further work. Typecasting was a real problem and roles sparse. Before taking on the role she was became a founding member of the Everyman Theatre in her native Liverpool. Upon leaving the series worked as a supply teacher at a girl's school in Kennington, before returning to the theatre. Small TV roles followed in series such as Emergency-Ward 10 and Z Cars.
In 1979 O'Brien played Morgan le Fay in the BBC adaptation of The Legend of King Arthur and she later won the role of Elizabeth Straker in the medical drama Casualty. Other roles included appearances in Cracker, Bergerac, Jonathan Creek, The Bill, Heartbeat and A Touch of Frost.
In addition to televison work O'Brien has had an extensive career in the theatre both as a performer and a director. In 1986 she was awarded the Time Out's Critic's Choice for her production of Mike English's Getting In . She has twice won the Sony Best Actress award for her work on radio and also has awards for audiobooks of which she continues to record a huge range.
In 1989 she had her first novel published, Close-Up on Death featuring the character of Detective Inspector John Bright. Six more novels featuring the character followed. She is also a playwright with her play The Cutting nominated Best Play in the London Fringe Awards and Best Newcomer in the Evening Standard Drama Awards.
Maureen O'Brien has returned to the role of Vicki in the Companion Chronicles produced by Big Finish. In 2013 she appeared at the 50th Anniversary Festival in London talking about her time with the series and her affection for the first Doctor.
My role was to laugh Bill out of his five or six tempers each day. I did it very happily. He was a charming creature in spite of his irascibility. He was very fond of me, and I of him.
Sources: Official Website; The End of the Line - documentary produced by Ed Stradling for the DVD release of The Gunfighters; The Handbook: The First Doctor – The William Hartnell Years: 1963-1966, David J Howe, Mark Stammers, Stephen James Walker (Doctor Who Books, 1994)