The actor Meg Wynn Owen, who has died aged 82 after suffering from dementia, was at the heart of the action in the TV period drama Upstairs Downstairs when it was at the height of its success. She played Hazel Forrest, the secretary who marries the son of the aristocratic Bellamy household at 165 Eaton Place, Belgravia, London.

Owen joined the series for its third run, in 1973, two years after the programme first captivated viewers with its tales of masters and servants above and below stairs in the first three decades of the 20th century. By then, it had built up an audience of up to 300 million in 50 countries.

She left at the end of the third series, in 1974, when Hazel died of Spanish flu days before the end of the first world war. Owen was always keen to move on to new pastures and originally had to be persuaded to take the long-running part.

Later, in the cinema, she was in one of the most memorable scenes of the 2003 romcom Love Actually. Playing the secretary of Hugh Grant’s prime minister, she discovers him dancing around Downing Street to the Pointer Sisters hit Jump (For My Love).

Meg was born in Lancaster, to Margaret (nee Brinnand) and Miles Shuttleworth. Aged 13, she left her family to be brought up in the Yorkshire West Riding village of Hoyland, near Barnsley (now part of South Yorkshire), by Ruth Wynn Owen, an actor and friend of her mother, and Ruth’s husband, Ian Danby, a former reporter on the Yorkshire Post who was working as a sales rep in the coal industry.

Ruth, who had performed on the West End stage, was a drama coach and producer of local plays – the actors Patrick Stewart and Brian Blessed were among her students. From the age of 14, Meg performed in her productions. Then, on graduating from Rada in 1956, taking the professional name Meg Wynn Owen, she gained repertory theatre experience in Swansea, Pitlochry, Birmingham and Sheffield.

She regularly acted in BBC radio plays from 1960 to 2005, including roles as Catherine Linton in Heathcliff (1967), Elizabeth Jane in The Mayor of Casterbridge (1968-69) and the title part in Jane Eyre (1972).

Owen made her first impact on television in The Franchise Affair, a 1962 adaptation of Josephine Tey’s mystery novel about the alleged kidnapping and beating by a mother and daughter of a 15-year-old war orphan, Betty Kane, played by Owen. She was then seen in Sunday-teatime serials, starring as Ann Farrance, also involved in a kidnap drama, in The River Flows East (1962) before playing Annie Ridd in Lorna Doone (1963).

A year later, she took the title role in Esther Waters, based on George Moore’s Victorian novel about a young kitchen maid who becomes pregnant and brings her child up as a single mother. Then came the part of Ruth King, one of the family running a sail-driven barge transport business, in King of the River (1966-67).

After Upstairs Downstairs, Owen remained a prolific character actor on television, with roles such as Anne Shakespeare, the Bard’s wife, in the 1978 series Will Shakespeare, and Elizabeth Harte, mother of Emma, the Yorkshire servant who becomes one of the world’s richest women, in the 1985 American mini-series adaptation of Barbara Taylor Bradford’s novel A Woman of Substance.

Her occasional film parts included the maid Lily Smalls in the 1971 version of Under Milk Wood; Lewis, maid to Lady Sylvia (Kristin Scott Thomas) in Gosford Park (2001); Lady Crawley in Vanity Fair (2004); and housekeepers to the Darcy family in Pride & Prejudice (2005) and Hugh Jackman’s murderous aristocrat in Scoop (2006).

On stage, she played Gwendolen Carr in the Royal Shakespeare Company production of Tom Stoppard’s play Travesties at both the Aldwych and Albery theatres in 1975. She and the cast then performed it in a five-month run on Broadway (1975-76).

Owen was married to William Wright from 1967 to 1987, becoming Margaret Wright, before the marriage ending in divorce. She died in June this year, but the news of her death became public only five months later, when a costume designer friend was jailed for swindling Owen out of her life savings.

• Meg Wynn Owen (Margaret Shuttleworth), actor, born 8 November 1939; died June 2022