Expert Witness in Lucy Letby Trial Did Not Disclose Hospital Investigation
The police force responsible for prosecuting former nurse Lucy Letby has stated it was not informed by a key expert witness that he was under investigation for serious concerns about his medical work before he testified at her trial. The Crown Prosecution Service has also confirmed it was unaware of the formal investigation into Professor Peter Hindmarsh by his employing hospital prior to his first court appearance on 25 November 2022.
Critical Evidence in Insulin Cases
Hindmarsh provided crucial evidence for the prosecution's case that Letby had attempted to murder two babies, referred to as F and L, by injecting insulin into their fluid bags. His testimony formed a significant part of the prosecution's argument during the high-profile trial.
The Guardian revealed last week that University College London Hospitals NHS Trust, Hindmarsh's main employer, was conducting a formal investigation into multiple serious concerns about his professional conduct in the period leading up to the trial. Great Ormond Street Hospital was also involved in this investigation, which included allegations that Hindmarsh had harmed patients.
Disclosure Rules for Expert Witnesses
Rules governing criminal cases require expert witnesses to disclose to the side they are representing anything "that might reasonably be thought capable of undermining the expert's opinion or detract from the credibility or impartiality of the expert." Senior legal experts have confirmed that these disclosure duties can include investigations by an expert's employer, such as the one conducted into Hindmarsh's professional conduct.
Glyn Maddocks KC, joint secretary of the all party parliamentary group on miscarriages of justice, emphasized: "As I understand the rules, in order to be open and transparent with the court, this expert should have disclosed this investigation, so that its relevance and importance could be assessed. It's vitally important that the integrity of experts is retained at all times."
Tim Green KC, a barrister experienced in disclosure rules, noted that while he couldn't comment on the specifics of the Letby case, generally an expert would be expected to disclose an internal investigation by their employer, particularly if it had reached an adverse conclusion.
Contract Termination Before Trial
Lucy Letby was convicted of murdering seven babies and attempting to murder seven others in the neonatal unit of the Countess of Chester hospital over two trials in 2023 and 2024. The insulin cases where Hindmarsh testified were pivotal in her conviction and represented two of only three guilty verdicts on which the jury was unanimous.
Hindmarsh was one of eight expert witnesses for the prosecution. An eminent figure in British medical practice, he served as a consultant paediatric endocrinologist and clinical director for paediatrics at University College London Hospital, while also working as an honorary consultant at Great Ormond Street Hospital.
However, his contract was terminated by the hospital in July 2022, four months before he gave evidence at the trial. Cheshire police confirmed that Hindmarsh did not disclose this termination to them. When he first appeared as an expert witness in November 2022, Hindmarsh was asked whether he was an honorary consultant at Great Ormond Street but did not make it clear that his contract had been terminated.
Delayed Disclosure to Authorities
Ultimately, Great Ormond Street referred its concerns about Hindmarsh to the General Medical Council, which opened an investigation into his fitness to practise on 25 November 2022 - the same day he first gave evidence in the Letby trial. University College London Hospitals also reported its concerns to the GMC.
Great Ormond Street informed Hindmarsh of the referral on 30 November 2022. Hindmarsh then disclosed 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 jury at the trial was never informed about these investigations.
The allegations against Hindmarsh were never finally adjudicated because in November 2024 he removed himself from the GMC register of doctors through a process known as "voluntary erasure."
Legal Implications and Response
A spokesperson for Cheshire police stated: "The professor made a disclosure to Cheshire police in December 2022 and we then notified the CPS." A CPS spokesperson confirmed: "We can confirm we are not aware of any disclosure being made by Prof Hindmarsh to the police until December 2022."
Mark McDonald, Letby's lawyer, said he would now be submitting Hindmarsh's non-disclosure of the hospitals' investigation as further evidence in support of an application to the Criminal Cases Review Commission. The CCRC is currently reviewing an application that argues Letby's convictions are unsafe and should be referred back to the court of appeal.
"Given the importance of Prof Hindmarsh's evidence, I am astonished that he did not disclose, before he gave evidence, that his contract at Great Ormond Street had been terminated and that he was under investigation," McDonald stated. "His failure to disclose these matters in itself raises questions over his credibility and integrity."
In response to questions from The Guardian about his disclosure, a representative for Hindmarsh said: "We have no comment at this time."
The case continues to raise significant questions about disclosure requirements for expert witnesses in criminal trials and the integrity of evidence presented in court proceedings.
