In 1955, the 16-year-old Mary Isobele Catherine O' Brien, living in London, of Irish descent, sat in front of a mirror, stared at her "chubby tomboy" face, national health glasses and "short mousy red hair" and said "you'll never make it, Mary. You're too dull and boring. You'll be a librarian." This, according to Lucy O'Brien's 1991 biography, Dusty, signalled the beginning of the metamorphosis that would, in time, kill off Mary O' Brien, give birth to Dusty Springfield and leave her at the mercy of psychological tensions that bedevilled her all her life.

But let's look first at the music, which is where Dusty Springfield's story begins. Take You Don't Have To Say You Love Me: Dusty was such a perfectionist that she did 47 takes of that song, pushing a full orchestra beyond breaking point, before she finally said "OK". From the start of her solo career, at a time when most female singers recorded what was chosen by their record company, Dusty called the shots, choosing the material she wanted to record.

First up was I Only Want To Be With You because she loved "the tune, the tempo" according to songwriter Ivor Raymonde, who also became the singer's producer and later remembered how Dusty developed her reputation for being "difficult" in the studio. "Dusty was an exacting artist. Bad musicians would annoy her, the tempo had to be just right, and before a session, the key had to be set so it wasn't too high or low. She was a perfectionist, like me, so we got on well."

A sense of insecurity apparently never let go of Dusty Springfield. She may have kicked off her legendary debut album, A Girl Called Dusty, with a raw slice of r'n'b entitled Mama Said, which beautifully expressed her desire to "be Ray Charles," but, deep down, Springfield always felt she wasn't the "real thing". That is, black. In fact, years later, while recording one of the greatest soul albums of all time, Dusty In Memphis, she was described by Atlantic Records producer Jerry Wexler as the "most insecure singer" he ever met. Dusty responded by saying: "What he didn't realise is how intimidated I was. Because they were talking about Aretha (Franklin) and I'm going `what am I doing on this label? Why are they recording me?' and that showed in the time it took to get vocal performances out of me." One hopes that, before she died, someone did make Dusty Springfield realise that being black is not the sole criterion for being a soul singer. In fact Dusty, at her best, was a better soul singer than many of her black peers. Her version of Son Of A Preacher Man certainly, is better than Aretha Franklin's. It's subtle, mysterious and poetic.

Sadly, her sense of self-acceptance seemed to evaporate over the following decade. Particularly after she moved to the US, which later led her to admit: "the loss of conviction is not an overnight thing". This comment seemed to apply not just to her music but the fact that, around this time, Dusty developed a dependency on drink and drugs "to combat feelings of isolation and frustration," according to her biographer, Lucy O' Brien.

O'Brien also suggests that "Dusty gradually lost her focus and sense of self", quoting the singer: "I felt I was obsolete, with a feeling of uselessness and depression." This feeling seems to have lingered during her final years, despite her "comeback" with The Pet Shop Boys.

There is a moral here for all of those pop stars who seek to "reinvent" themselves. Be careful the beast you create doesn't eat you alive. That, in the end, rather than cancer, just may have been what finally "killed" Dusty Springfield. Or rather, Mary O' Brien.