The deaths of nine additional babies were not included on the graph presented at Lucy Letby’s trial because they were not deemed unexpected or suspicious, the Mail has learnt.
The neo-natal nurse was convicted of murdering seven babies under her care, between June 2015 and July 2016.
But another nine babies also died on the unit at the Countess of Chester Hospital from January 2015 until Letby was removed from working the following summer.
Statisticians who have written to the Government questioning the safety of Letby’s convictions insist the graph, which compared 25 suspicious collapses or deaths with nurses on duty and showed Letby present every time, was flawed because it failed to include other fatalities or unexplained events.
But sources have told the Mail that the nine deaths were investigated and deemed irrelevant to the trial because they were explicable and could be put down to natural causes.
The source said: ‘Four of the deaths were babies born with a congenital problem or birth defect, another baby was sadly asphyxiated or deprived of oxygen at birth, the remaining four died of infection and their deaths were precipitated with a period of time consistent with infection – they did not suddenly and unexpectedly collapse and die.’
The Mail understands that Letby was on duty at times when at least two of these babies were being treated on the neo-natal unit, although it is not known if she was ever their designated nurse.
Professor Jane Hutton, a statistician from Warwick University and one of 24 experts to have written to ministers asking for the upcoming public inquiry into Letby’s crimes to be postponed or its terms of reference expanded, told The Trial podcast she was concerned about the graph because information about the other nine deaths ‘wasn’t there’.
Professor Hutton, an expert in survival analysis, admitted she had only read a ‘summary’ of the Court of Appeal’s judgement, from three of the country’s most senior judges who refused Letby leave to appeal her convictions in July.
Tim Owen KC, a barrister experienced in cases involving miscarriages of justice, said the claims being made by statisticians were erroneous because it was clear from that Court of Appeal ruling that Letby’s case was ‘not prosecuted on the basis of statistical probability’.
‘The graph of when Miss Letby was on duty was simply there to demonstrate that she had the opportunity to inflict harm, not that, because she’s on duty, she inflicted harm,’ he said. ‘The prosecution case was not a statistical probability case.’
Mr Owen said that, while Letby’s appeal had failed, there was still the avenue of the Criminal Cases Review Commission for her to pursue, should new evidence emerge to suggest her conviction was unsafe.
‘But it will require compelling evidence,’ he added.