Angela Morley was a versatile musician, a composer, arranger and conductor, who began her professional life as Wally Stott and became nationally known in the 1950s as a stalwart of The Goon Show before undergoing a sex-change.

The change of gender, and its unwelcome publicity, ushered in a difficult period in her private life, but she was able to pick up her career, eventually moving to the United States where she worked on a number of popular films and television shows.

She was born Walter Stott in Leeds in 1924. His father was a watchmaker and owned a shop selling watches, jewellery and silver plate. A musical memory was of sitting on the floor surrounded by records of the Jack Payne and Henry Hall bands and playing them on a wind-up gramophone.

At eight he started piano lessons but these came to an end when his father died suddenly a few months later. He toyed briefly with the violin and accordion before taking up the clarinet and playing in the school orchestra. Next it was an alto saxophone and a first taste of band music, performing under Bert Clegg at the Empress Ballroom in Mexborough, South Yorkshire.

He left school at 15 and toured with a juvenile band for ten shillings a week. His career started to take off during the Second World War when bands were losing musicians to the forces. The young Wally Stott spent a couple of years going from band to band until, at 17, he joined Oscar Rabin as lead alto.

In 1944, aged 20, he joined the Geraldo Orchestra, familiar to millions through its BBC radio broadcasts. As the orchestra played in various combinations, from swing band to symphonic, Stott was able to hone his skills as an arranger, inspired by two masters of the craft, the Canadian-born Robert Farnon and Bill Finegan, who worked for Tommy Dorsey.

The self-taught Stott decided it was time to seek professional instruction and studied harmony, counterpoint and composition with the Hungarian composer Matyas Seiber and took a conducting course with Walter Goehr.

At the beginning of the 1950s he gave up playing to concentrate on writing, arranging and conducting. He became musical director of the new Philips record label, began to write film scores and moved into broadcasting on The Goon Show and Hancock’s Half-Hour.

Disillusioned with the quality of recording in the cinema he turned down film offers for some years, but in the late 1960s he wrote music for The Looking Glass War, When Eight Bells Toll and Captain Nemo and the Underwater City. After the sex change operation in 1972 he became Angela Morley, taking his mother’s maiden name, and for a while she put her career on hold. But by 1974 she was working on Stanley Donen’s film The Little Prince, with the songwriting team of Lerner and Loewe, and she went on to collaborate with Robert and Richard Sherman on the score for Bryan Forbes’s Cinderella story The Slipper and the Rose. Both films brought her Oscar nominations. In 1977 she was the credited composer on Watership Down, an animated film based on Richard Adams’s novel. Malcolm Williamson had originally been commissioned and wrote what became the first six minutes of music on the film, but had to withdraw through illness. At this period Morley was also a regular conductor of the BBC Radio Orchestra and worked with John Williams on the orchestration of his scores for Star Wars, Superman and The Empire Strikes Back.

She attended the two Oscar ceremonies at which she was nominated, and liked California so much that she settled there in 1980. From then on her work was in the US, much of it for television on such shows as Dallas, Dynasty, Falcon Crest, Cagney and Lacey and Wonder Woman.

She helped John Williams with his scores for E.T., Hook, the Home Alone films and Schindler’s List and won three Emmy awards for arranging.

Over the years life in Los Angeles became steadily less appealing and after the 1994 earthquake, with its epicentre only six miles from her house, she made her home in Scottsdale, Arizona. Here she founded the Chorale of the Alliance Française of Greater Phoenix, for which she wrote more than 30 arrangements of French songs.

Wally Stott was married twice. His first wife, who founded the Beryl Stott Singers, predeceased him, as did a daughter. In 1970 he was married to Christine Parker and, despite the trauma of the sex change only two years later, she and Angela Morley stayed together.

Morley is survived by her and a son.

Angela Morley, conductor, composer and arranger, was born on March 10, 1924. She died on January 14, 2009, aged 84