Kate O'Mara obituary

The actor Kate O'Mara, who has died aged 74 after a short illness, was always surprising. She appeared in the television series Dynasty as Caress Morell, the bitchy sister of Joan Collins's Alexis Colby, and played vampish femme fatales in horror movies. But her physical glamour and bad-girl facade was a mask for an always serious and beguiling artistic personality.

She came from a theatre family – five generations of actors and actor-managers, including JW Boughton, her great-grandfather, a theatre owner in Southsea, Hampshire, and friend of Charles Dickens. A dedicated Shakespearean, she gave definitive performances as Beatrice in Much Ado About Nothing and Titania in A Midsummer Night's Dream in the Open Air theatre, Regent's Park, London.

She also appeared with the Royal Shakespeare Company, in the lead role of Lilli Vanessi in a tour of Kiss Me Kate (1991), but her major performances were invariably off-piste, in repertory theatres, or on Bill Kenwright tours. In the mid-1990s she gave one of those touring roles, Mrs Cheveley in Oscar Wilde's An Ideal Husband, at no fewer than three West End addresses: the Haymarket, the Albery (now the Noël Coward) and the Globe (now the Gielgud).

However, she was best known to the British public as a stalwart of many popular television soaps – The Brothers (1975-76), Dynasty (1986), Howards' Way (1989-90), a revival of Crossroads (2003) – and one of the worst, too, the execrable Triangle (1981-82), a North Sea ferry saga that even the BBC, which had produced the programme, included on an evening of worst-ever TV shows.

Kittenish and seductive – her friend Roger Moore once dubbed her "Starlet O'Mara" – she counted Lydia Languish in Sheridan's The Rivals, which she played for the Welsh Theatre Company in 1965, and Elvira in Noël Coward's Blithe Spirit as her favourite roles. But she more than cut the mustard, too, as Cleopatra at the Nottingham Playhouse in 1982 and as Martha in Edward Albee's vitriolic Who's Afraid of Virginia Woolf? on a 1990 tour.

O'Mara, born in Leicester, was christened Francesca Meredith Carroll, the daughter of John Carroll, an RAF flying instructor, and his wife, Hazel Bainbridge, a busy touring actor who took the children with her wherever she worked. Her younger sister is the actor Belinda Carroll, who always called her Merrie. She was expelled from a convent school in Woking but persisted in taking her O-level exams on her own and going on an exchange trip, somehow, to learn French.

When Hazel settled for a few years at the Worthing Rep in West Sussex, her elder daughter trained at the Aida Foster School in London and made her film debut (in 1956) as Merrie Carroll in Vernon Sewell's Home and Away, playing Jack Warner's daughter alongside Kathleen Harrison and Thora Hird. She made a television debut in 1957, but then decided to go backstage while pursuing her interests as a pianist and an artist, being talented in both spheres.

She worked as a wardrobe mistress at Glyndebourne, with wigs at Stratford‑upon-Avon, and then as a teacher in a girls' school in Burgess Hill, West Sussex. As Belinda took up acting, so Merrie decided to revert to the boards and made a professional stage debut in 1963 as Jessica in The Merchant of Venice at the Flora Robson Playhouse, Newcastle upon Tyne. Her London debut followed in 1968 when she took over as Elsa in The Italian Girl at Wyndham's.

In between, she worked in rep in Guildford, Watford, Bromley and Leatherhead – she was, in a way, the wicked queen of the home counties – before exploding all that experience into her television work in the 1970s, when she appeared as Jane Maxwell, the tough boss of an air freight business, in The Brothers; and as a sexy bad girl on film in Roy Ward Baker's The Vampire Lovers, Jimmy Sangster's hilarious spoof The Horror of Frankenstein (both 1970) and Blake Edwards' cold war love story The Tamarind Seed (1974), starring Julie Andrews and Omar Sharif.

Later television work included Howard's Way, guest appearances on Morecambe and Wise and The Two Ronnies – always playing up to her vampish, siren-like reputation – and a telling drop-in on Absolutely Fabulous as Patsy Stone's sister, Jackie. In the mid-1980s, she played one of the renegade Time Lords, The Rani, in Doctor Who (vintage Colin Baker, then Sylvester McCoy), tinkering with other people's biochemistry and looking terrifying.

She used her professional clout, and funds, to set up The British Actors' Theatre Company in 1987 with Peter Woodward. I most remember her, though, in this period not just as Beatrice and Titania, but as Katherina in The Taming of the Shrew and Mistress Ford in The Merry Wives of Windsor with David Conville's New Shakespeare Company in Regent's Park. She was also a notably fine Goneril in King Lear for Anthony Quayle's touring Compass Theatre.

Her life was clouded in disaster when her son, Dickon, a former RSC stage manager, hanged himself on the last day of 2012 in the home he shared with her at Long Marston in Warwickshire. Though she was a trim, perennially fit advertisement for taking good care of oneself, a vegetarian and teetotal all her life, this was a blow from which she never really recovered.

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In 2008, she had enjoyed a great critical success as Marlene Dietrich in Lunch with Marlene at the New End in Hampstead (Frank Barrie played Noël Coward) and had most recently been seen in Benidorm, the ITV soap, and touring with the Agatha Christie Company in Murder on the Nile in 2012.

She wrote two novels and two volumes of autobiography, Game Plan: A Woman's Survival Kit (1990) and Vamp Until Ready (2003).

In 1961 she married the actor Jeremy Young. They divorced in 1976. Her marriage to Richard Willis, 18 years her junior, in 1993 ended in divorce three years later.

She is survived by Belinda.

Kate O'Mara (Francesca Meredith Carroll), actor, born 10 August 1939; died 30 March 2014