There is “absolutely” a strong case that Lucy Letby is innocent, her new barrister has said ahead of a fresh attempt to appeal the serial child killer’s convictions.

Mark McDonald said new medical evidence and expert opinion revealed “flaws” which undermined the prosecution of the former nurse, who was found guilty in two trials.

Letby was convicted of the murders of seven babies and the attempted murders of seven others, with two attempts on one child, when she worked on the neonatal unit at the Countess of Chester Hospital between June 2015 and June 2016.

Asked on Channel 5 News whether there was a strong case for her innocence, Mr McDonald said: “Absolutely, there is. And I will be drafting the application to the Criminal Cases Review Commission (CCRC).

“You know, I’ve been so encouraged by the amount of people that have come forward: experts in neonatology, anaesthetists, pathology, statistics; that have come forward and have identified flaws in the trial that now want to give evidence for her, and we’ll want to draft reports to put in to the CCRC to assist.”

Letby is serving 15 whole-life orders – making her only the fourth woman in UK history to be told she will never be released from prison.

Mr McDonald added: “We’re looking really at issues in relation to statistics. And I know that sounds probably quite bizarre to hear, ‘well, what statistics got to do with it?’

“You may remember that there were some bold assertions made during the trial in relation to, for example, (that) there was a spike of deaths, she was always on duty, when in fact, when analysed by some of the leading statisticians in the country, they’re seeing flaws in those assertions made by the prosecution to such a fundamental extent we believe it undermines the conviction.”

New medical evidence, which contradicts that presented by prosecution experts at the trial, has also been brought forward, Mr McDonald said.

“We’re looking at neonatology for a start,” he continued.

“We’re looking at the whole idea in relation to insulin, the testing of insulin, whether or not that testing was reliable, whether or not that the assertion that there was insulin present is accurate.”

The barrister added he would be asking the CCRC for Letby’s case to be sent back to the Court of Appeal “on fresh evidence” but said the process “might take a long time”.

Letby’s trial ran for 10 months from October 2022 to August 2023, with a retrial ordered after a jury was unable to reach a verdict on one count of attempted murder of a baby girl.

Mr McDonald compared Letby’s conviction to that of the Guildford Four and Birmingham Six – two groups of people wrongly accused of carrying out IRA pub bombings in the 1970s whose convictions were later quashed.

“These were some of the biggest miscarriages of justice in UK history, and yet they were found to be innocent,” he said.

The barrister added that he had so far seen “quite a lot of evidence that there are some real concerns” over Letby’s convictions.

A public inquiry examining events at the Countess of Chester Hospital following Letby’s multiple convictions is due to begin on September 10 in Liverpool.