By Steven Shukor
BBC News, London
A computer analyst who has given expert testimony in highly sensitive court cases is being investigated over concerns about his credibility.
Mr Bates has worked on dozens of Operation Ore cases
Jim Bates has served as a witness in dozens of cases related to Scotland Yard's inquiry into internet child pornography, Operation Ore.
But doubts have been cast over his competence after it emerged he had misled a court about his qualifications.
Shy Keenan, of Phoenix Survivors, which offers support to child abuse victims, said Mr Bates should not be allowed to work as an expert witness while he is under investigation.
"Surely his involvement in such matters should be suspended at least until after the very serious questions regarding his alleged qualifications and expert status have been officially dealt with."
"This matter could potentially lead to a review of all involved cases or indeed further proceedings."
Mr Bates told BBC News he accepts he erred in claiming he had a Bachelor of Science in Electronic Engineering in court documents.
He is under investigation by the Child Exploitation and Online Protection (CEOP) centre, which is affiliated to SOCA (Serious Organised Crime Agency).
But he accused CEOP of harassment and leaking information to the media in an attempt to "discredit" him after highlighting what he claims were serious flaws with several Operation Ore investigations.
Mr Bates is president of the Institution of Analysts and Programmers (IAP) and has been involved in high-profile cases as an expert witness both for the prosecution and defence.
He was used as an expert witness for the Metropolitan Police against Gurpal Virdi, the Sikh officer wrongly accused of sending racist hate mail to himself and colleagues.
However, Mr Virdi was exonerated and reinstated with a formal apology in 2000 after an employment tribunal ruled he had been the victim of racism.
Mr Bates has previously served as an advisor to Scotland Yard's computer crime unit and lectured at the police training school at Bramshill.
In court papers dated September 1998 seen by BBC News, Mr Bates states: "I hold a Bachelor of Science degree in Electronic Engineering".
In 2004, it emerged that he held no such qualification and had never been to university.
The Crown Prosecution Service (CPS) has since advised its prosecutors to "challenge his credibility" in cases where Mr Bates appears as a defence witness.
"Prosecutors would have to disclose to the defence that allegations have been made against Mr Bates if we were using him as a prosecution expert," said a CPS statement.
"If he was appearing as a defence witness it may be appropriate to challenge his credibility."
Mr Bates said he now mainly works as an expert witness for defence teams, including cases involving child pornography on the internet, but that the credibility allegations were hindering him.
"One of the effects of being targeted like this means that as an expert witness, counsel will understandably be reluctant to employ me directly because of such issues regarding my integrity," he said.
He said he has been gathering evidence to prove certain officers involved in Operation Ore had been careless with their investigations with a view to clearing his name.
"I have evidence to prove Operation Ore was based on a completely false series of premises and police officers should have been aware of this if they had done their job properly," he said.