Child serial killer Lucy Letby’s retrial for the attempted murder of a baby girl should not have gone ahead due to “overwhelming and irremediable prejudice” caused by media coverage of her first trial, the Court of Appeal has been told.

Letby, 34, is seeking approval to challenge her most recent conviction for trying to kill the newborn, known as Child K, after being found guilty following a retrial in July.

Three senior judges will decide whether the former nurse’s case can proceed to a full appeal following Thursday’s hearing in London.

Benjamin Myers KC, for Letby, told the court that the attempted murder charge should have “stayed” as an “abuse of process” due to “overwhelming and irremediable prejudice” caused by media coverage of her first trial.

He said: “The learned judge was wrong to reject the application made by the defence at the outset of the trial to stay the indictment as an abuse of process.”

He continued: “It is an exceptional case, with exceptional media interest, and therefore exceptional unfairness is capable of arising, notwithstanding the safeguards that are often employed.”

He added: “We are dealing with the impact of media coverage and public comment arising from the first trial, upon the second.”

Mr Myers said that media coverage before the retrial was “saturated with unadulterated vitriol towards Ms Letby”, which included coverage on the BBC’s Panorama and ITV’s Loose Women which “described her as evil and depraved”.

He continued that “the media coverage following trial one, particularly in the immediate aftermath” included “highly prejudicial and emotive public comment by police officers in charge of the investigation” while a retrial was still under consideration.

The court heard that comments by police and members of the Crown Prosecution Service (CPS) created “powerful prejudice against the defendant while simultaneously bolstering their own status”, which Mr Myers said “should offend the court’s sense of justice and propriety”.

He continued: “It really is not what should happen at all and in the circumstances of this case, bearing in mind all that had already happened, the public interest could be met by finding that there was an abuse (of process).”

Letby, formerly of Hereford, watched the hearing via a video link from HMP Bronzefield, wearing a green dress.

She was previously sentenced to 14 whole life orders after being found guilty at her first trial of the murders of seven babies and the attempted murders of six others, with two attempts on one child.

Her offences occurred at the Countess of Chester Hospital’s neonatal unit, where she worked as a nurse, between June 2015 and June 2016.

Following that trial, which ran from October 2022 to August 2023, the jury was unable to reach a verdict in the case of Child K, but a second jury took just three-and-a-half hours to convict her at the retrial at Manchester Crown Court.

Jurors were told she targeted the “very premature” infant during a night shift at the Countess of Chester Hospital in the early hours of February 17, 2016 by dislodging Child K’s breathing tube after she was moved from the delivery room to the unit’s intensive care unit.

She was sentenced to her 15th whole life order for the offence, which the sentencing judge, Mr Justice Goss, said was “another shocking act of calculated callous cruelty”, describing Child K as “exceptionally vulnerable”.

After being sentenced, Letby said “I’m innocent” as dock officers led her away.

The CPS is opposing the appeal bid, with Nick Johnson KC stating in written submissions that it was “misguided” and that the jury found Letby to be a “multiple killer and habitual liar”.

He said: “The application appears to rely on the huge volume of publicity as being of itself sufficient grounds on which to base an application to stay the indictment.

“It also leans heavily on the proposition that it is wrong for a witness to speak to the news media and that fact in itself taints the prosecution to the extent that it should be stayed.

“This is a misguided approach.”

In court, Mr Johnson said that 62 pieces of publicity had been provided by Letby’s barristers to support the appeal bid.

Responding to Mr Myers’ claims, he said: “We do not, for a minute, accept that’s anything like a reasonable or accurate characterisation.

“What was said by police in the aftermath of the convictions in the first trial was reasonable and it accurately and moderately described the horrendous offences (for) which this applicant had been convicted.”

Letby previously had a bid to appeal against her first set of convictions dismissed by the Court of Appeal in May.

A court order prohibits reporting of the identities of the surviving and dead children involved in the case.

The hearing before Lord Justice William Davis, Lord Justice Jeremy Baker and Mrs Justice McGowan, which is expected to conclude on Thursday, continues.