The police force behind the prosecution of former nurse Lucy Letby has said a key expert witness did not inform it before testifying at her trial that she was under investigation over serious concerns in her medical work.
The Crown Prosecution Service also told The Guardian that it was not aware that Professor Peter Hindmarsh was subject to a formal investigation by the hospital that employed him, before his first appearance as a witness on 25 November 2022.
Hindmarsh provided crucial evidence at trial to the prosecution’s case that Letby had attempted to murder two babies, known as F and L, by injecting insulin into their fluid sacs.
The Guardian revealed last week that in the run-up to the trial, University College London Hospitals NHS Trust (UCLH), Hindmarsh’s main employer, was leading a formal investigation, involving Great Ormond Street Hospital, into multiple, wide-ranging and serious concerns, including allegations that Hindmarsh was harming patients.
The rules governing criminal cases require expert witnesses to disclose to the party to whom they are giving evidence (in Hindmarsh’s case, Cheshire Police) anything “that may reasonably be considered likely to undermine the expert’s opinion or diminish its credibility or impartiality”.
Senior lawyers have told the Guardian that these disclosure duties can include investigations by an expert’s employer, such as that into Hindmarsh’s professional conduct.
Glyn Maddocks KC, joint secretary of the all-party parliamentary group on miscarriages of justice, said: “As I understand the rules, to be open and transparent with the court, this expert should have disclosed this research, so that its relevance and importance could be assessed. It is vitally important that the integrity of the experts is maintained at all times.”
Tim Green KC, a lawyer with experience in disclosure rules, said he could not comment on the details of the Letby case, but generally an expert would be expected to disclose an internal investigation by his employer, particularly if it had reached an adverse conclusion.
“If the inquiry report were to criticize the competence and ability of an expert witness, I would expect a doctor experienced in giving expert evidence to disclose the trust’s investigation into him/her to solicitors seeking their opinion. This is to enable instructing solicitors to ensure that the expert complies with the disclosure rules before giving evidence.”
Hindmarsh contract terminated before trial
Letby was found guilty of murdering seven babies and attempting to murder seven others in the neonatal unit of the Countess of Chester hospital, in two trials in 2023 and 2024.
The two insulin cases were instrumental in Letby’s conviction and were two of only three guilty verdicts in which the jury was unanimous.
The former nurse has always maintained that she is innocent. In February last year, his lawyer Mark McDonald made an application to the Criminal Cases Review Commission claiming the convictions were unsafe and should be returned to the appeal court.
The CCRC is reviewing the application, which is supported by reports from 27 experts, including a panel of leading UK and international doctors led by Canadian neonatologist Dr Shoo Lee. They say the prosecution’s medical evidence, including that of Hindmarsh, was flawed, that the babies died from natural causes and poor care in the unit, and that there was no evidence of murder, insulin poisoning or any other deliberate harm.
Hindmarsh was one of the prosecution’s eight experts. He was an eminent figure in British medical practice; Consultant pediatric endocrinologist (hormone specialist) and clinical director of paediatrics (children’s medicine) at University College London Hospital. He was also an honorary consultant and worked at Great Ormond Street, the world-famous children’s hospital.
However, the hospital terminated his contract in July 2022, four months before he testified at trial. Cheshire Police confirmed Hindmarsh also did not disclose this to the force.
When he appeared as an expert witness for the first time in November 2022, Hindmarsh was asked by Nick Johnson KC, senior solicitor for the CPS, if he was an honorary consultant at Great Ormond Street. Hindmarsh did not make it clear that his contract had been terminated.
‘No disclosure until December 2022’
In the end, Great Ormond Street referred its concerns about Hindmarsh to the regulator, the General Medical Council. The GMC opened an investigation into Hindmarsh’s fitness to practice on November 25, 2022, the same day he first gave evidence for the Letby prosecution. UCLH also subsequently reported its concerns to the GMC.
Great Ormond Street informed Hindmarsh of the referral on 30 November 2022. Hindmarsh then revealed to Cheshire Police on 14 December 2022 that he was under investigation by the GMC. Both the police and CPS told the Guardian that this was the first disclosure he had made. The trial jury was never informed of the investigations.
The allegations against Hindmarsh were never ultimately tried, because in November 2024 he was removed from the GMC’s doctors’ register, a process known as “voluntary deletion”.
A Cheshire Police spokesperson said: “The professor made a disclosure to Cheshire Police in December 2022 and we then notified the CPS.”
A CPS spokesperson said: “We can confirm that we are not aware of any disclosures made by Professor Hindmarsh to police until December 2022.”
McDonald said he would now present Hindmarsh’s confidentiality of the hospitals’ investigation into him as additional evidence in support of the CCRC’s application.
“Given the importance of Professor Hindmarsh’s evidence, I am surprised that he did not disclose, before giving evidence, that his contract at Great Ormond Street had been terminated and was under investigation. His failure to disclose these matters raises questions about his credibility and integrity.”
In response to questions from The Guardian about his revelation, a representative for Hindmarsh said: “We have no comment at this time.”
