Fresh concerns have been raised about the handling of the Lucy Letby case by Cheshire Police and the Crown Prosecution Service, as the nurse's new barrister prepares an application to the Criminal Cases Review Commission. Mark McDonald, who now represents Letby, said he is working with leading neonatologists who have identified alternative medical explanations for the babies' deaths and collapses.
The concerns include the use of a shift chart at Letby's first trial, which statisticians have criticised as an example of the 'prosecutor's fallacy'. Professor Jane Hutton of the University of Warwick described the chart and other evidence as 'a large pile of crockery, much of which is broken'. The Thirlwall inquiry has heard that the police investigation was initially based on statistical coincidence.
Documents show that in May 2017, seven doctors reported to police that Letby was present at 11 of 13 deaths, adding that the likelihood of this occurring by chance was 'very low'. However, hospital managers told the inquiry that when they approached Cheshire Police, they acknowledged there was no specific allegation of a criminal act at that point.
Emails reveal that in April 2018, a police officer contacted Professor Hutton asking for a statistical probability that one nurse could be on duty during all deaths. Hutton advised that a proper investigation should consider all possible explanations, including medical conditions and unit performance, rather than focusing on one individual from the outset. Despite initially engaging Hutton, Cheshire Police proceeded with the investigation.
The application to the Criminal Cases Review Commission is expected to challenge the safety of Letby's convictions, which include seven murders and seven attempted murders at the Countess of Chester Hospital. The Court of Appeal refused Letby permission to appeal in May, but her legal team continues to pursue further scrutiny of the case.
