Killer nurse Lucy Letby is set to mount a new legal challenge against her latest conviction next month.
The 34-year-old was given a 15th whole life sentence in July for the attempted murder of newborn at the Countess of Chester Hospital’s neonatal unit.
She was already set to die behind bars after being found guilty of the murders of seven babies and the attempted murders of six others.
It comes after experts at the Royal Statistical Society (RSS) expressed concerns over the key piece of evidence against her – a chart showing she was always on duty when newborns collapsed or died.
The table seen by jurors at her trials covered her killing spree between the summers of 2015 and 2016 and showed that while 38 other nurses were on shift when some of the babies collapsed or died, Letby was present on every occasion.
It was considered one of the most damning pieces of evidence against Letby.
But statisticians were so worried about the use of the data that they convened a meeting at the RSS headquarters in London on Thursday to discuss how statistics are used in court.
During the meeting, the rota pattern was described as a ‘scientific fake’ which could not be reproduced independently, according to The Telegraph.
(Picture: Elizabeth Cook/PA Wire)
The meeting was held under Chatham House rules which allows attendees to remain anonymous.
Statisticians warned that there were ‘issues with the selection and collection of data’ used in the chart, said that there could be ‘many other possible causal factors not being considered that might explain the deaths.’
The duty roster evidence was describes as ‘feeble’, and was said to have had ‘a way bigger impact than it deserves.’
Experts argued that alternative explanations were not given enough attention, such as the different shift patterns of the nurses and whether some were more likely to be on duty than others.
The meeting heard that statistical evidence was ‘worthless’ and that there had been no clear evidence of a spike in deaths at the hospital.
Speaking after the meeting, Dr Jane Hutton, a professor of statistics at the University of Warwick, said: ‘It’s a large pile of crockery, much of which is broken. Such a pile does not hold water however big it is.
‘We’re not saying the conviction is unsafe, but we consider that if the concerns we are raising are essential to the decisions of the court, then the convictions are unsafe.’
The meeting heard that similar shift pattern data was used to convict a Dutch paediatric nurse and Italian nurse Daniela Poggiali, both of whom were subsequently exonerated.
Statisticians warned that statistics were being ‘abused by the courts in the way that it’s used in trials’.
(Credits: Cheshire Constabulary/PA Wire)
Speaking to Metro earlier this month, Letby’s new barrister Mark McDonald said the statistical evidence was one aspect of the prosecution case he is examining.
He said of the collapses in Letby’s case: ‘The statistical assertion was put before the jury to say there was a spike in deaths and that she was always on duty at the time of those deaths or when a patient has died that they feel is suspicious.
‘That analysis – that bold assertion – made by the prosecution, I think, is undermined by their failure to engage with statisticians to actually look at the comparative nature of the neonatal units.
‘Not a month goes past that we don’t hear of an obstetric unit or a neonatal unit or a children’s department having been criticised for its failure to have proper procedures in place, or its failure to have proper protections in place for its children and high death rates.
‘Without actually engaging with statisticians to do a comparison with a number of different units and looking at the full shift rota and doing it in a way that is blind – so they don’t have what is called confirmatory bias and a belief that this is the person we’re looking for, now let’s see when she was on duty and let’s see if there are any unusual deaths – that is the wrong starting point.
‘It needs to look at the different units to see whether or not there has been a spike and then look at the variables within that unit.’
(Picture: Cheshire Constabulary/PA Wire)
Members of the RSS said they were asking for parity in court cases, with statisticians invited to be present if statistical evidence was shown to the jury.
‘If toxicology was represented you would expect a toxicologist to be present’, they said.
On Friday, staff at the Court of Appeal confirmed the former nurse was bringing a bid to appeal against her conviction for attempted murder in July.
Judges will consider the case at a hearing on October 24, according to court listings.
A public inquiry into the events surrounding Letby’s crimes, chaired by judge Lady Justice Thirlwall, began at Liverpool Town Hall earlier this month.
The judge said inquiry hearings would finish in early 2025 and she expected to publish her findings by late autumn of that year.
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