Jazz singer Anita Wardell has established a reputation for her vocal improvisation. She talks to Miriam Craig ahead of her appearance at the Mill Hill Music festival

Anita Wardell first heard scat singing - vocal improvisation using nonsense words, or without words at all - when she was at teacher's college.

It's an art form that gives a singer the ability to create the equivalent of an instrumental solo using his or her voice.

Wardell fell in love with it immediately and, with advice from the people who had been training her to become a music teacher, she went to The University of Adelaide, in Australia, to study jazz.

It's for this skill and her allegiance to the bebop tradition - a form of jazz characterised by fast tempos and improvisation - that Wardell, 46, has become known.

She says: "If they want to define me like that, I'm very happy. That's what makes me different."

More recently the 2006 BBC Best of Jazz award-winner also mastered the skill of vocalese, a style of jazz singing where lyrics are set to music that was originally part of an instrumental composition or improvisation.

On her album Noted, she put lyrics to instrumental solos from ten classic Blue Note recordings. Her sixth and latest album, Kinda Blue, is a return to straight songs, although two of the tracks also contain vocalese.

She says: "I love those songs and I wanted to have a relationship with the lyrics this time, rather than the scatting or instrumentals. It still keeps that niche that I'm in, but gets a different crowd of people to listen to my music."

Wardell was born in Guildford but moved to Australia with her family as a child, and at the age of 27 she returned to England, where she now lives.

Over the course of her career - one that has involved her singing alongside jazz legend Sarah Vaughan - she has witnessed and been part of the resurgence of jazz, in particular of female jazz singers.

She says: "It's really bizarre. During the Eighties, it was all Ella Fitzgerald and Sarah Vaughan and Betty Carter, who had been around since the Fifties, and no new people had really come through.

"When Diana Krall came on the scene, it was suddenly fashionable for everybody to be coming out about being a jazz singer and getting some recognition for it. And since the Nineties I've noticed a huge surge."

But she admits this rise in popularity is a double-edged sword; it has created a market for the kind of music she makes, but on the other, she says: "It's hard to make a name for yourself when jazz singing has already received so much attention. But if you're good, you will get noticed.

"I'm one of those people who's always looking for new ways to reinvent the music. Bebop is where my heart lies and I want to put a contemporary edge to it. It's an art-form that's always growing."

But she still has one unfulfilled ambition: "One of my great aims is to sing in a group, but not as a singer - as an instrumentalist," she says.

"Once when I was at college the trumpet player didn't turn up to a rehearsal, and I was asked to sing the trumpet line. That's some of the best fun I've ever had."

Anita Wardell will perform on Wednesday at 8.30pm, at the Mill Hill Sports Club, in Grahame Park Way, as part of the Mill Hill Music Festival. Tickets cost £7 (members £5) and are available from Nomad Travel travel agent in Mill Hill Broadway, or the box office on 020 8906 9991.

Other performers taking part in the festival include Sir John Dankworth, the Steve Taylor Big Band, and the Dixieland Jazz Band.