The email arrived at the Herald two weeks after the July 7 London bombings. The sender, anonymous but for the address "obsandgobsfitzy", wrote:

I thought you would like to know one of the heroines from the Tavistock Sq bus bomb was a Kiwi.

She was one of the medics working at the British Medical Association who immediately rushed out to help people. When police decided they needed to move people immediately, she was asked if she would board the bus to provide medical support.

She agreed, despite being told the device could detonate ... she then joined other emergency services in the courtyard of the BMA and treated casualties for around three hours.

When asked, she just said that it wasn't brave, it was just the "ethical and moral thing to do". She won't accept any praise, but I feel New Zealand should be proud.

It was something a closely involved, admiring colleague might write. At that point it wasn't obvious that the sender of the email was also the subject, the beginning of a final act of a deception that would end with her lonely death in her Shepherd's Bush Rd bedsit last week.

Richmal-Marie Oates-Whitehead was born in February 1970 in Gisborne, where she attended Lytton High School before beginning training as a radiation therapist in 1989. The course ran for three years: one in the classroom and two as a trainee at Auckland Hospital.

The hospital didn't keep her on afterwards, so Oates-Whitehead sought work elsewhere.

She spent some time working in a junior management role for the Waikato health authority and gained a post-graduate diploma in health service management from Massey University in 1997.

Odd behaviour surfaced in the late 1990s. Oates-Whitehead, apparently an epileptic, started seeing an Auckland doctor, but things ended badly after the doctor suggested she needed psychological help. One day while the doctor was overseas, Oates-Whitehead turned up at her church, where she had a spectacular fit.

The doctor feared she was being stalked when their paths crossed again in 1999.

Oates-Whitehead attended a training workshop which taught volunteers how to do reviews for the Cochrane Collaboration, an international grouping of health professionals, of which the doctor was a member.

Working in groups, members collect and analyse research to help doctors put it into practice. Non-doctors work alongside experienced medics. 

Another Cochrane member, a psychologist, says Oates-Whitehead didn't claim any qualifications other than those she had, and threw herself into the reviews, the first on blood clots.

"It was all high-quality work," she says. "She was an intelligent woman."

Eventually she became an editor of groups on respiratory infections, breast cancer and gynaecological cancer. Her mother Marilyn, who suffered from cancer, and a nurse cousin are cited as helpers in several reviews.

Oates-Whitehead "probably felt quite included and accepted" by Cochrane members, says the psychologist: the atmosphere is collegial, supportive and non-competitive.

Although Oates-Whitehead was "charming", she says there was something "odd" about her. "One minute she would be your best friend, the next she wouldn't even speak to you. You felt you had to take everything she said with a grain of salt."

She complained of numerous miscarriages and other health worries: she was having chemotherapy, a treatment for cancer, she had heart problems, she had multiple sclerosis, she had suffered renal failure, she had undergone a double knee replacement.

"I got the impression that everyone had a few doubts about the health stories, but put up with it," says the Auckland doctor.

In 2001, Oates-Whitehead moved to Britain, intending to stay long-term. By December, she was apparently working for the NHS Wales in an analyst role, but kept up her Cochrane work.

From April 2002 to November last year, she worked for the Royal College of Paediatrics and Child Health's research arm as clinical effectiveness co-ordinator, managing the process of appraising evidence-based clinical practice.

"This was responsible and demanding work, but did not require a medical qualification," says a spokesman.

A British doctor with an inside view of RCPCH said opinion of Oates-Whitehead's work was "very positive. She worked incredibly hard - even overworked. She was doing it to the exclusion of everything else".

But Oates-Whitehead's fantasy was taking flight. She started signing herself "doctor" and "obstetric epidemiologist" to outsiders.

Epidemiologists, who study the incidence of disease, are generally medical doctors or have at least masters or PhD qualifications.

Doubting New Zealanders who queried the new title were told of British medical qualifications gained through cross-credit study. Their doubt increased when Oates-Whitehead said she was doing a doctorate and a master's degree side-by-side - an arrangement few universities, if any, would sanction.

The curious claims were not just limited to her professional life. A posting on announced the birth and death of twins after 20 weeks' gestation.

"To Richmal, Michael, big sister Sophie and grandma Marilyn, in London. Two beautiful angels, Jemima Josephine and Molly Niamh. Born by caesarean section on the 7th of August 2004, passed away in Mummy's arms on the 8th of August 2004. Now in heaven."

A similar notice appeared in the Herald two weeks later and two more the weekend after. Sympathy poured forth but the babies never existed. Michael Fitzgerald, said to be a hospital obstetrician, and a stepdaughter, Sophie, never existed.

The nurse cousin visited Oates-Whitehead in London last year but realised something was up the day she tried to find Fitzgerald, without success. She told Richmal by phone, jokingly, that her fiance needed to introduce himself to colleagues so people would recognise him.

"She got all upset, and said 'I've got to go'. Then she rang me back five minutes later: 'I've just found out Michael's been lying to me and he's been off work for the last six months because he's had a heart attack'."

The cousin saw no sign of a significant other in the studio flat where Oates-Whitehead lived alone - no pictures, no men's clothes. Her niggles became major worries, and once home, she shared them with her parents but not Marilyn Oates.

"I thought: nobody's life is that complicated and this exciting. Something was a bit fishy, but I had no proof."

Oates-Whitehead's London life appeared quite sterile. "All she does is sit there and read ... because she's got no life ... that's why she's created this wonderful life."

In November last year, a jubilant Oates-Whitehead reported she had been awarded a personal academic chair and the title professor, and had started a job with Euro RSCG Life Medical Education, a marketing agency, with the title clinical obstetric epidemiologist.

She emailed a friend in New Zealand:

Last week I was in Italy for work but came home for the weekend, and on Monday I flew to Switzerland, also for work, and came back yesterday, so I really need some sleep. I keep thinking that as I have got my chair (being a prof was always in the game plan), and have got the 'wow' job, and I'm still only 34, life's great and all the work has paid off. However, I would swap it all for Molly and Jemima being alive.

Early this year, using a document claiming she was a medical doctor, Oates-Whitehead landed a well-paid, non-doctor job at the British Medical Association's BMJ Publishing Group.

She joined a team of editors on the publication Clinical Evidence, which summarises medical knowledge. In her office she kept a stethoscope and a blood pressure kit.

When terrorist bombs claimed 14 lives in Tavistock Square outside the BMA building on July 7, it triggered what would be her final deception.

After sending the anonymous email to the Herald, Oates-Whitehead was initially hesitant when contacted by a reporter, but eventually spoke for more than an hour.

She was friendly and spoke plausibly of helping as firefighters hurriedly prised survivors from the wreckage. There was "no room for hesitation", she said.

The day after the story ran, the disbelieving calls about her qualifications started. Challenged, Oates-Whitehead became defensive and then threatened legal action. But she stuck to her story.

However, her wildly varying justifications for medical degrees didn't stack up. Oates-Whitehead has never been registered in New Zealand or Britain as a doctor. What, then, was her role on the day terrorism visited Tavistock Square?

The Herald understands an emergency staffer did approach in search of a medic while Oates-Whitehead was standing with her immediate boss, GP David Tovey, and BMJ editor Fiona Godlee outside the BMA building.

The senior pair were diverted on to other tasks at that moment, and there is no proof that Oates-Whitehead boarded the bus.

The BMA refuses to clarify. But post-bomb accounts of its staffers' heroics published on its website did not name her. A source said there was "considerable doubt what her role was on the day".

Family members were confused. "I don't know what to believe any more," said one. 

Six days after the original story ran, "obsandgobsfitzy" sent the Herald an angry email:

I am furious and distressed at what has unfolded. I have told Richmal the roll [sic] I played in this story because I felt terrible about how upset it made her.

In her true style she has been exceedingly forgiving. To persecute someone who's acted with such courage and selflessness in unimmagineable [sic] circumstance [sic], and who did it while so incredibly ill, is unforgiveable.

I have been a friend of Richmal's for years and I was there on that dreadful day. When the police ask [sic] her if she was a first-aider or health professional and she answered yes, and they asked her would she then come to the bus ... she didn't hesitate to go, after all she was an amazingly talented health professional, despite me begging her otherwise (I had heard the full exchange).

The extra stress you have put on her by your inexcuseable [sic] behaviour has caused the illness which she has been so bravely battling to deteroriate [sic], and she has today spent the day in hospital. I hope you are very proud. I know I'm not.

An hour later, a New Zealand colleague received an email which Oates-Whitehead said she was writing from hospital where she had been diagnosed with an alarming raft of problems, including the bleeding disorder von Willbrand disease, an auto-immune condition and multiple sclerosis.

I think I must have been very bad in a past life, killed lots of mongolians or something.

After that, silence. But allegations had reached her employers' ears. Two days later, Oates-Whitehead's employer confronted her. She resigned on the spot and left immediately, claiming ill-health. The BMA launched a fraud investigation.

On Wednesday, August 17, police responded to a call from Marilyn Oates who, unusually, hadn't heard from her daughter for 24 hours. Officers found her body at her flat.

The Fulham coroner carried out a post-mortem the next day. Oates-Whitehead apparently had multiple medical problems, but the cause of death was pulmonary embolism. Blood clots had travelled from both legs to lung arteries, blocking oxygen supply. Her last breaths would have been struggling gasps.

Some colleagues jumped to the conclusion it was suicide. Corrected, they were surprised. One admitted to some guilt at having ignored the constant complaints of ill-health.

Oates-Whitehead's mother and an aunt flew to Britain, arriving last Tuesday morning. They hope to bring her body home.

Colleagues speculate that Oates-Whitehead had a severe personality disorder. Clinical psychologist Nick Wilson says sufferers are often liars - telling people what they want to hear to be liked.

Although practised at displaying a polished face, they are fragile, have poor self-esteem and are often lonely: they allow certain people to see slices of their lives. But no one sees the whole, lest they are exposed and rejected.

"People with severe personality disorder learn to survive on superficial engagements," says Wilson. "They might go out for coffee with friends from work, and in their own mind will turn that into a date. They live off the crumbs, and in a Walter Mitty way will turn that into a full meal."

Oates-Whitehead got away with it because her lies were largely successful in a place where she knew few people and was unlikely to be challenged.

For several years she maintained her grip, fashioning a life of medical drama, academic success and anecdotes of family activities with "Michael and Sophie". The doubters kept their silence and the lies swelled.

In one chatty email back to New Zealand, Oates-Whitehead cheerily signed off with the line:

I personally find that life can be improved if you're not quite in touch with reality!

All too soon, that reality caught up with her.

- additional reporting by Derek Cheng