Evelyn Rothwell was one of the most distinguished oboists of her time and as Lady Barbirolli cared loyally and unselfishly for her husband John Barbirolli especially during his years as conductor of the Hallé Orchestra. Though diffident about playing under his baton, she was occasionally persuaded, and made some fine concerto recordings with him. After his death she became a busy teacher and adjudicator, who knew how to convey firm views with tact and kindness, and who won the deepest respect and affection throughout the musical world.

Born at Wallingford-on-Thames, Evelyn Rothwell was the daughter of a tea dealer. She was educated at Downe House, where, aged 17, she was first given an oboe. She later studied with Leon Goossens - the greatest oboist of his era, who brought prominence to the instrument - at the Royal College of Music. Her time there coincided in part with Benjamin Britten's, who occasionally asked her to try pieces composed for another oboist, and for whom she once assembled a small orchestra to play his newly completed Sinfonietta. She was also one of a group of students engaged by Covent Garden as non-singing extras for Mussorgsky's Boris Godunov with the famous bass singer Chaliapin.

At the age of 20 she received a letter from John Barbirolli suggesting she audition for a place in the Covent Garden Opera touring orchestra (his brother Peter, a viola player, had noticed her when she deputised in the Drury Lane orchestra). It was the first time they met, and she was appointed second oboe. She also played for a number of London shows, often filling in at short notice for Goossens. In 1933 Barbirolli became conductor of the Scottish Orchestra (now the Royal Scottish National Orchestra) inGlasgow and asked Rothwell to be principal oboe. She accepted, and soon appeared as the soloist in a Handel concerto and other pieces arranged for her by Barbirolli.

The seasons lasted only five months, and in her spare time Rothwell went back to freelance work, with the London Symphony Orchestra and with Fred Hartley's Quintet for Radio Luxembourg broadcasts, and played at Glyndebourne, after taking part in its first season in 1934. In 1936 she was appointed first oboe of the Queen's Hall Orchestra under Sir Henry Wood.

That year Sir John Barbirolli was invited to New York, and was soon appointed as Toscanini's successor at the Philharmonic. While he was negotiating his contract in New York, Rothwell continued to play for the Scottish Orchestra. She turned down an offer of marriage from its new conductor, George Szell, and in 1939, after Barbirolli was divorced from the singer Marjorie Parry, they were married, and she went to live with him in New York.

During the darkest days of the Second World War, however, Barbirolli was tormented by what was happening in Britain. He was also very homesick, worried about his family, and, by refusing to take American citizenship, had been unable to join the American Musicians' Union. In February 1943 he received a telegram from Manchester, inquiring if he was interested in rebuilding the shattered Hallé Orchestra. “This is it,” he said to Rothwell, and within a matter of weeks the appointment had been made. At the beginning Rothwell was effectively his secretary and driver, and would often be present at rehearsals, moving around at the back to assess the balace of sound. As Barbirolli greatly valued her judgment and honest analysis she also listened in the control box as music was being recorded.

Rothwell was still sought after as a chamber musician, partly thanks to celebrated recordings she made years before with the Busch Quartet, and now also as a soloist. She was admired for her sensitive powers of interpretation and the beauty of her tone, and at one time she was giving up to 80 concerts a year as well as teaching advanced students.

At Salzburg in 1948 gave with the Halle Orchestra the first performance of the reconstructed Oboe Concerto by Mozart. She became associated with the concertos of Strauss and Martinu, and concertos written for her by a number of British composers - including Rubbra and Rawsthorne - also featured in her repertory, as did arrangements by her husband of 18th century Italian pieces by Pergolesi and Corelli.

Nevertheless, she continued to organise her husband's domestic and professional life with the greatest loyalty and efficiency, planning her provincial tours to coincide with his extensive travelling at the helm of the Hallé Orchestra, and when in the 1960s Barbirolli became, in addition, music director of Houston Symphony Orchestra, she she began to travel with him on their tours too as often as she could. “It merely sharpens my appreciation of our home life” was her reply to suggestions that she might tire of life on the move.

As a teacher, colleague and in her busy and demanding role as Barbirolli's wife, she made a strong mark upon the musical world. Her tremendous warmth and integrity of character, and her generous humour, also made her one of the best loved musicians of her generation, and one whose company was sought as keenly as her musical judgement. (She was an excellent raconteur, one story capturing the moment when, arriving on stage for a performance and finding no stand, she pinned her music to the back of a convenient curtain - which promptly rose, leaving her to improvise as best she could.)

Unfortunately, from 1947 onwards there was barely a year when Barbirolli, who was knighted in 1949, did not suffer injury or ailment including, in 1957, a dramatic ten-feet fall from the Free Trade Hall podium. Like his doctors, Rothwell did all she could to persuade him to slow down. But on July 29, 1970 - two months after a priest friend performed a religious wedding ceremony for them, Barbirolli's Roman Catholicism having been an obstacle years before - he died, after rehearsing the New Philharmonia Orchestra for an imminent tour of Japan.

A few months before, Rothwell had spoken in an extensive interview to mark his 70th birthday about life with a great conductor. “When your husband is a public figure he needs someone who can be - well, like an old slipper, easy and comfortable,” she said. “He needs a safety valve, somebody he can grumble at, somebody he has no need to be polite to. Somebody, I suppose, that he loves.”

Life at home, she explained, was relaxed. “We prefer the simple pleasures. We dress in old clothes, John cooks the dinner - he's awfully good at it - and we have a bottle of wine, and we listen to the wireless. People who are at the beck and call of the public need to go back to the simple pleasures, to a bit of family life. You must have at least one person in your life you can rely on completely, one person to whom you can say anything, one person with whom you can be yourself. For John, I hope, I am that person.”

After her husband's - and now taking the professional name Evelyn Barbirolli - she taught at the Royal Academy of Music and further developed her activities as writer and adjudicator, while gradually curtailing her public appearances as a player. Her name frequently appeared as president or patron of musical organisations, and she took an active interest in every organisation with which she was associated, particularly the Isle of Wight Oboe Competition where for many years she chaired the judging panel. She was also a dedicated supporter of the Musicians' Benevolent Fund.

Her scholarly bent had led Rothwell to make various transcriptions while still a student, and her later publications included an admirably practical book on oboe technique and, later, a pair of volumes forming the best modern tutor for the oboe. In 2002 she published an autobiography, Living with Glorious John.

She was appointed OBE for her services to music in 1984.

Lady Barbirolli, OBE, the oboist Evelyn Rothwell, was born on January 24, 1911. She died on January 25, 2008, aged 97