Stobart's career embraces much of the history of jazz and swing from the late 1930s onwards. Born in 1925 in South Shields, she was a pioneer in a male-dominated world. She followed in the footsteps of Britain's other great female swing pioneer, the multi-instrumentalist Ivy Benson. Benson, born in Leeds in 1913, started her career with Edna Croudson's Rhythm Girls, toured with Teddy Joyce and the Girl Friends, then formed her own band, which survived until the early 1980s. One of her finest hours was in 1943, when her orchestra became the official BBC Resident Dance Band, the papal blessing of the business. This infuriated several of her male counterparts, notably one Billy Ternent, who wanted the gig for his own band. History being what it is, Ternent is now remembered more for his chauvinistic outbursts about Benson than for his somewhat sugary music.

 

Like many of her generation, Stobart looks back on the war as the best of times and the worst of times. She spent its early years playing twice-nightly variety on the music-hall circuit with a swing band that, she says, "swung like a bucket of lead".

 

"We visited all kinds of places that were being bombed and if there was a raid on after the show was over, we would continue with a band show. And little Kath came into her own: I was up there dancing and impersonating and pulling the roof down, because I was a kid, only 14."

 

Eventually the government closed the theatres because of the bombing and the band was stranded in Brixton. Stobart returned to the north-east where she found work at the Oxford Galleries dance hall in Newcastle, again as a result of an audition where her singing, dancing and impersonations got her the job in spite of her saxophone-playing. In addition to the regular dances every evening, she played afternoon tea dances and Sunday concerts at a cinema in the city. "I was playing 11 times a week. If you can't learn doing that you're never going to learn."

 

At this time she met Keith Bird, a London-based jazz musician serving in the RAF and passing through the north-east. He liked the tone of her playing and introduced her to jazz, coaching her during the tea breaks. "He'd play a chord on the piano and say: play what you can hear in there. I could feel my fingers buzzing on the beat. He found out I had perfect pitch. And that was it."

 

Bird encouraged her to move to London and take over his regular job with a quartet at the Montague Ballroom in Ealing, because he was being posted to Outer Stornoway. She slipped into a routine, rushing away after her Ealing job - "They used to let me off the last waltz" - and taking the underground to the Jamboree Club in Wardour Street, Soho, where she played late-night jazz in a band led by trumpet player Dennis Rose. "We'd play till five in the morning and if there was an air raid we'd keep on going. Dennis used to say, 'If you hear anything funny dive under the piano - a building can fall on a grand piano.'"

 

It was in this ambience that she met a Canadian pianist and bandleader called Art Thompson, her first husband. "I wish I'd been a bit older because I knew nothing about it. What a fool. Eighteen and all I knew about was music."

 

She was a member of the Art Thompson band that moved into the prestigious Embassy Club, though not without opposition from the management. "They said, 'We'll have problems right away. A woman in the band, all those people hanging round, soldiers - problems right away.'" The solution was to dress Stobart exactly like the rest of the band, in a tuxedo with a skirt instead of trousers. Such trouble as there was came not because of her, however, but from the young RAF pilots in the balcony above the bandstand who used to take flying leaps over the heads of the musicians on to the dance floor.

 

Stars would often pass through the club - Glenn Miller, Bing Crosby, Clark Gable, David Niven, Bob Hope and the Andrews Sisters, among others. Stobart's most poignant memory is of the night Glenn Miller got drunk. He was normally the most modest of drinkers, but they noticed him sitting for the first time ever with a glass full of whisky in his hand and found him, much later, propped up against a wall, "absolutely legless".

 

"We took him down this alley in Piccadilly, we nearly dragged him, and the waiter had a taxi there and Art pushed Glenn into the back seat, gave the driver 10 bob and said, 'Please take this officer to such-and-such a club.' And that was it. Next thing we knew was that Glenn had taken off for Paris ahead of his band ... and nobody ever saw him again. We were among the last people to see him."

 

In 1947 Stobart, who had split with Thompson, joined the Vic Lewis Big Band, which sought to echo the "progressive" jazz being played in the US by the Stan Kenton Orchestra. She stayed with Lewis for 10 years, with time out in 1949-50 when, with Bert Courtley, her second husband, she formed her own band. "It was a dead loss from the off because somebody put me into ballrooms," she says. "They weren't the right places for jazz. Especially ours, which was quite modern jazz. We started to lose money straight away."

 

After the band folded, she rejoined Vic Lewis and toured Europe playing military bases in a package also including the American singer Herb Jeffries, who had worked with Duke Ellington, and a young Morecambe and Wise. The 1950s were a hectic period when she somehow juggled her musical career with giving birth to three sons. Ivy Benson frequently complained about losing entire sections of players, virtually overnight, to various aspects of domesticity - especially when the American GIs arrived in the UK. Stobart did her best, continuing to play for the first six months of each pregnancy.

 

The thought that she was a pioneer in a male-dominated world never occurred to Stobart until later. "The thing was that once they found you could do it, you had respect. That's all. They'd say, 'By gosh, yes, good!'"

 

The decline of the big bands in the late 1950s transformed the music business. Since 1957, Stobart has alternated spells in the Humphrey Lyttelton band with tours as a solo artist. The 1960s were complicated by the dual responsibilities of bringing up three sons and caring for a sick husband. Courtley, a wonderfully gifted musician in a fragile shell, died in 1969, aged 40. In the 1980s Stobart began touring with her own quintet. Ronnie Scott described her as one of his favourite tenor sax players, "either European or American, male or female". She still performs today, although she stopped touring when the long-distance driving made her medical advisers twitch.

 

She is reluctant to claim role-model status but under pressure admits this might have been the case. "That lovely trombone player, Annie Whitehead, she's written that, as far as she was concerned, I was pointing the way for women. And by God, she doesn't half play. She did a few deps with Humphrey's band. She's played all styles, including all the free-form you like, but she went through all the music, read it all, the Ellingtons, the Basies, everything."

 

Whitehead has a CV that, astonishingly, embraces work with Ivy Benson and subsequently with the Brotherhood of Breath (led by the great South African in exile Chris McGregor) and the Sisterhood of Spit. She is one of many remarkable women of the postwar generations working in jazz and related areas (the definitions are increasingly slippery in modern music) on both sides of the Atlantic, including such diverse talents as Barbara Thompson, Nikki Yeoh and Holly Slater in this country, Regina Carter, Toshiko Akiyoshi and Jessica Williams in the US. Indeed, I would argue that the most important jazz-based musician working in the big band arena, and the natural successor to Duke Ellington, Charles Mingus and Gil Evans, is the American pianist/composer/bandleader, Carla Bley.

 

And if the history of women's part in popular instrumental music reflects the slow but inevitable changes in women's part in society generally, it simply proves what CLR James didn't quite get around to saying: what do they know of swing bands who only swing bands know?