The secret life of Dr Brooke Magnanti, an obscure research scientist, is revealed today as she unmasks herself as the writer behind the pseudonym Belle de Jour.

Her identity has been one of the great literary mysteries of the decade after the publication of bestselling books about her secret life as a prostitute.

Magnanti is a respected specialist in developmental neurotoxicology and cancer epidemiology in a hospital research group in Bristol. Six years ago, in the final stages of her PhD thesis, she ran out of money and turned to prostitution through a London escort agency, charging £300 an hour. Already an experienced science blogger, she began writing about her experiences in a web diary that was adapted into books and a television drama starring Billie Piper.

There has been huge speculation about Belle’s real identity, including a theory that she was a well-known author because of the quality of her writing. The blog and books were also criticised for suggesting prostitution could be glamorous. Last week Magnanti contacted one of Belle’s sternest critics, India Knight, the Sunday Times columnist, saying she wanted to reveal her identity.

The scientist, a petite 34-year-old, has no regrets about her 14 months as a prostitute. “I’ve felt worse about my writing than I ever have about sex for money,” she said. Anonymity had become “no fun”, however: “I couldn’t even go to my own book launch party.”

Until last week, not even her agent knew her real name. A month ago she revealed her secret to her colleagues at the Bristol Initiative for Research of Child Health, who were “amazingly kind and supportive”. She was preparing to tell her parents this weekend.

Magnanti said she was working on a doctoral study for the department of forensic pathology of Sheffield University in 2003 when she took up prostitution. “I was getting ready to submit my thesis. I saved up a bit of money. I thought, I’ll just move to London, because that’s where the jobs are, and I’ll see what happens.

“I couldn’t find a professional job in my chosen field because I didn’t have my PhD yet. I didn’t have a lot of spare time on my hands because I was still making corrections and preparing for the viva; and I got through my savings a lot faster than I thought I would.”

When she could no longer afford her rent, she started to think: “What can I do that I can start doing straightaway, that doesn’t require a great deal of training or investment to get started, that’s cash in hand and that leaves me spare time to do my work in?”

She found an escort agency and started her secret life. “I did have another job at one point, as a computer programmer, but I kept up with my other work because it was so much more enjoyable.”

Her future lies in medical science, but she also has a literary streak. She has been writing a novel, and the Belle blog will “continue for a bit — I’d like her to have happy ending”.

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