Health chiefs in south-west London are to begin a review into how a woman could masquerade as a nurse for 15 years despite never qualifying.
Valerie Cook, 56, worked for at least five GPs in the NHS area now managed by Sutton and Merton Primary Care Trust.
Since 1988 she carried out smear tests and vaccinations despite never having passed her nursing exams in the 1960s.
But checks were carried out when she applied for a job as clinical governance co-ordinator with Sutton and Merton Primary Care Trust earlier this year.
'Carried out minor surgery'
A spokeswoman for the trust said it was the first case of its kind in the area.
Independent reviewers would be working with the five surgeries involved to find out "how and why this happened", she added.
Cook, of Haynt Walk, Merton Park, south London admitted deception at Wimbledon Magistrates' Court on Thursday.
Prosecutor Tony Levy told the court she had "administered drugs,
inoculations and carried out minor surgery" over the past 15 years.
'Not a charlatan'
The magistrates agreed to commit the case to crown court, where heavier sentences can be handed down.
Cook's solicitor Laura McQuilley agreed the charges were serious, but said her client was not a "charlatan" and had an excellent record as a nurse.
She added that Cook had trained as a nurse for a year but had to give up when her parents fell ill. She had since passed a district nurse's exam.
The subsequent decision to masquerade as a qualified nurse was "a stupid
mistake" and Cook had been "devastated" by her arrest, said Ms McQuilley.
The results of the review will be shared with the rest of the NHS, said Sutton and Merton Primary Care Trust.