The NHS has written to more than 2,000 patients warning them they could
have been examined by a bogus doctor.
Barian Baluchi, who claims to be a consultant psychiatrist at the Kimia Clinic in central London, is under investigation by police.
Mr Baluchi specialises in work with asylum seekers and refugees suffering post-traumatic stress disorder.
The Westminster Primary Care Trust letter urged worried patients to return to their GP or ring the police.
Mr Baluchi prepared psychiatric reports on up to 1,500 asylum seekers funded by legal aid, Channel 4 News reported.
A spokeswoman for the health trust said: "We have written to all known
patients for whom there are records. That is about 2,300.
"Our main concern is the health and safety of our patients.
"We want to reassure them. We are encouraging them to get back to their GP,
contact their solicitor."
She said there were helpline numbers for concerned patients to call "if they
feel they may have been the victim of a crime or assault".
Fraud question
Channel 4 News said officials were concerned patients may have given Mr Baluchi confidential information.
A spokesman for the Metropolitan Police said no charges had been brought but
an allegation of an individual posing as a medical practitioner and obtaining
money by deception was received in June.
A 42-year-old was arrested in August and bailed to return to a central London
police station on 2 December, he said.
Mr Baluchi is understood to have come from Iran, but told the General Medical Council that he had qualified in Madrid.
The NHS Counter Fraud Service said it took allegations of fraud in the NHS very
seriously.
It said in a statement: "Whilst we cannot comment on ongoing
investigations, we take all allegations of fraud in the NHS no matter how big or
small very seriously.
"Every pound lost to fraud is a pound lost to the continuing improvement of
NHS front-line services."