Theatrical design, even if preserved in photographs, working drawings and models, still - like the essence of theatre itself - remains an ephemeral art, like sculpting in snow. But Julia Trevelyan Oman, whose work in theatre, ballet and opera, and on cinema and television screens, established her as a leading designer for over 30 years, also co-created (with her husband, Sir Roy Strong) an enduring legacy in the remarkable gardens of the Laskett, their house in Herefordshire, near Ross-on-Wye. She also wrote some memorable books in partnership with her husband, one of them most appropriately titled On Happiness (1998).

Julia Trevelyan Oman, who has died of cancer aged 73, was one of the great television, theatre and film designers of the late 20th century, but her work was steeped in historical research. The past was never another country to her. Indeed, she was born with history coursing through her veins: her mother, Joan Trevelyan, was a descendant of the Macaulays and the Trevelyans; her father, Charles Chichele Oman, was the son of a Chichele professor of modern history at Oxford University.

JULIA Trevelyan Oman, one of Britain’s leading theatre and opera designers, whose sumptuous sets enhanced productions of La Boheme, Swan Lake and The Importance of Being Earnest, has died at the age of 73.

Born in London, Trevelyan Oman studied at the Royal College of Art under Hugh Casson.

She joined the BBC in 1995 and remained there for 12 years, creating sets for shows, including the police series Dixon of Dock Green and the Billy Cotton Band Show.