She is the daughter of Edward Ward, 7th Viscount Bangor, and his fourth wife Marjorie Alice Banks. Her father was the BBC's war correspondent in Finland at the beginning of World War II, while her mother was a writer and BBC producer specialising in dramatised documentaries.
She has a brother Edward, two years her junior; and a half-brother, William, who is the 8th Vicount Bangor, three years her senior.
Through her father she is descended from George Plantagenet, 1st Duke of Clarence, brother of Edward IV, via John Mordaunt, 1st Earl of Peterborough, John, 1st Viscount Mordaunt, and Bernard Ward, 1st Viscount Bangor.
Ward's stage name, "Lalla", comes from her attempts as a toddler to pronounce her own name. She left school at the age of 14 because she "loathed every single minute of it", and took her O-Levels on her own. After spending a few years painting, Ward auditioned at London drama schools "as a sort of dare" to herself:
Ward studied at the Central School of Speech & Drama from 1968 to 1971.
She began her acting career in the Hammer horror film Vampire Circus (1972), and played the teenage daughter of The Dutchess of Duke Street in the popular BBC drama series of the 1970s. She appeared in films such as Matushka, England Made Me (1972), Rosebud (1974), and The Prince & The Pauper (1977) and on television featured in Van Der Valk (1973), The Protectors (1973), Quiller (1975), Who Pays The Ferryman? (1977), The Professionals (1978) (Iloved this show!) and Hazell (1979). She acted in a film called Got It Made in 1974 which was later recut with sex scenes featuring other actresses and reissued as Sweet Virgin. Club International magazine ran nude pictures from the film, claiming they were of her and Ward successfully sued the magazine. In 1980, she played Ophelia to Derek (Prf. Yana) Jacobi's Hamlet in the BBC television production.
She is best remembered as the second actress to play Time Lady Romana (Romanadvoratrelundar). After a guest appearance as Princess Astra in the Doctor Who story"The Armegeddon Factor" in 1979, Ward was chosen to replace Mary Tamm, who had decided against continuing in the role.
She appeared in ten televised Doctor Who serials credited as Romana - "Destiny of thev Daleks", "City of Death", "The Creature from the Pit, "Nightmare of Eden", "The Hornes of Nimon", "The Leisure Hive", "Meglos", and also the E-Space trilogy - "Full Circle", "State of Decay" and "Warriors Gaste". She also appeared uncredited in "Logopolis" and "Resurrection of the Daleks" during flashback sequences.
One story that Ward worked on, "Shada" was not completed due to a strike, and the material was only televised as part of the anniversary episode"The Five Doctors" in 1983.
Ward was dating her co-star Tom Baker whilst working on Doctor Who, and they lived together in a flat in Chelsea. After her exit from the programme in 1981, the couple married that December, but the marriage lasted only sixteen months. Ward and Baker later claimed their separation was due to work commitments, different lifestyles and conflicts of interest. Regarding her marriage to Tom Baker, Ward is quoted as saying:
"It's something I still feel sad about. I loved — and, in many ways, still love — Tom very much. The trouble is, our careers came to be just as important as each other, and we grew apart. I was angry at suggestions that it didn't work because I was too young, or that Tom was unreasonable to me. We just irritated each other occasionally — we weren't close enough, I suppose. It was a decision we discussed and felt was for the best."
After Doctor Who, she appeared in Schoolgirl Chums (1982) and The Jeweller's Shop and The Rehearsal on stage.
Ward decided to end her acting career after marrying Dawkins. However, she has since reprised the character of Romana in the 1993 charity special Dimensions in Time, the 2003 webcast version of "Shada", and in several Doctor Who and Gallifrey audio plays produced by Big Finish Productions. In addition, she has appeared at a number of Doctor Who conventions and related special events.