---
title: "Expert Allegedly Revised His Testimony on the Cause of Deaths in Lucy Letby Trial"
meta:
  "og:description": "Defense barrister argues that the prosecution's expert is not reliable because he revised his opinion in Lucy Letby trial"
  "og:title": "Expert Allegedly Revised His Testimony on the Cause of Deaths in Lucy Letby Trial"
  author: "Expert Witness Profiler"
  description: "Defense barrister argues that the prosecution's expert is not reliable because he revised his opinion in Lucy Letby trial"
---

# Expert Allegedly Revised His Testimony on the Cause of Deaths in Lucy Letby Trial

Posted on January 2, 2025 by Expert Witness Profiler

Between 2015 and 2016, Lucy Letby harmed babies in her care with the intention of killing them. The means of harm varied: causing air embolus by introducing air via intravenous lines; forcing air into the abdomen via nasogastric tubes; force feeding milk; poisoning by administering insulin; physical trauma. She alone was present on the unit at the time of all the deaths and deteriorations.

Following an internal review of the deaths, and the suspension of the applicant from nursing duties, the police began an investigation in May 2017. Letby was convicted in August 2023 of seven counts of murder and seven of attempted murder of infants at the neonatal unit at the Countess of Chester Hospital. She was acquitted on two further counts of attempted murder and the jury was unable to agree on a further six counts of attempted murder. The Court of Appeal rejected Letby’s application for leave to appeal against her convictions after the credibility of Prosecution’s lead expert, [Dewi Evans](https://expertwitnessprofiler.com/expert-witness/Dewi-Evans/1560556)‘ testimony was affirmed.

Evans, a retired paediatrician, was asked to review initially 33 sets of clinical records involving death or deterioration of an infant on the unit and then a further 28 sets of records.

He was retained to provide an opinion on the cause of the collapse of each baby. Lucy Letby’s barrister Mark McDonald told a news conference in London that Evans, had allegedly altered his view about how the babies died. Evans added: “Mark McDonald’s observations regarding my evidence is unsubstantiated, unfounded, inaccurate. Evans said the only change in his evidence related to the date a child referred to as Baby C died but insisted it was a simple error by the prosecution.

## **Pediatrics Expert Witness**

[Dewi Evans](https://expertwitnessprofiler.com/expert-witness/Dewi-Evans/1560556) provides expert medical advice regarding clinical issues where child abuse is suspected or where there are allegations of clinical negligence. He has prepared reports for the Court for over 25 years and has given evidence in court in Wales, England, Ireland and Northern Ireland.

He was appointed a consultant paediatrician in 1980; he had been trained in neonatology although, at the time, this was not a specific sub-specialty, hence he was never a consultant neonatologist; he set up a neonatal intensive care service in Swansea; he designed a new neonatal unit in 1990.

[Get the full story on challenges to Dewi Evans’ expert opinions and testimony with an in-depth Challenge Study.](https://app.expertwitnessprofiler.com/login?eId=1560556)

## **Discussion by the Court**

“The defense will argue that Evans is not a reliable expert, and all the convictions are not safe,” McDonald said. He said: “Remarkably, Evans has now changed his mind on the cause of death of three of the babies: Baby C, Baby I and Baby P.

The Court was told that one of Letby’s victims, Baby C weighed just 800g (1lb 12oz) when he was born in early June 2015, but despite that, medics recorded that he was in a “good condition” and stable.

He was being kept in the highest priority section of the neonatal unit, but on the night of 13 June, he suddenly stopped breathing.

The Court heard Letby, who was the designated nurse in a different section but was present when Baby C collapsed, caused the issue at about 23:15 BST by inserting air into his stomach via a nasogastric tube.

Medics failed to revive him and he was pronounced dead at 05:58 on 14 June

According to McDonald, Evans had “revised his opinion in relation to Baby C” and had written a new report which he had given to police months ago. But, he added “despite numerous requests” the prosecution had “yet to give this report to the defense”.

Evans previously told BBC that Baby C was likely to have died due to “a combination of air and milk” pumped via the nasogastric tube into the stomach, which differed from what he had said in Court when he only mentioned air.

He told the BBC it had led him “to review the events leading up to Infant C’s collapse and death” and thought it “more likely” that it was an injection of air into the bloodstream, although he stressed either would be “inflicted injury”.

## **Key Takeaway**:

Mark McDonald accused Dewi Evans of retracting his earlier statements about how the babies died. Evans allegedly revised his opinion regarding Baby C but failed to provide the defense with his updated report.

However, Evans said he was “surprised how little he changed his mind” while working on the case.

Please refer to the blog previously published about this case:

[Lucy Letby Objected to the Prosecution’s Lead Expert’s Testimony Regarding the Collapse of Each Baby](https://expertwitnessprofiler.com/prosecutions-lead-experts-testimony-on-the-collapse-of-each-baby-admitted-despite-lucy-letbys-objections)

---

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