Lucy Letby murdered seven babies. Now she's been found guilty of trying to kill another one.

Former nurse Lucy Letby has been found guilty of trying to murder another newborn baby, adding to convictions from last year that made her the United Kingdom's most prolific serial child killer of modern times.

The newborn in question, referred to in court as Baby K, was a premature baby girl.

34-year-old Letby was found guilty last August of murdering seven babies and trying to kill six more between June 2015 and June 2016 while working as a nurse in the neonatal unit of the Countess of Chester Hospital in Chester, northern England.

She was served 14 whole-life prison terms and told she would never be released.

In a prior trial for the count of attempted murder of Baby K, a jury failed to reach a verdict. Now, she's been found guilty. Letby denied having harmed any baby in her care.

What happened to Letby's victim Baby K?

Image: Getty

Last month, she went on trial for a second time on one count of attempted murder of Baby K, a charge on which the original jury had failed to reach a verdict.

Prosecutor Nick Johnson told Manchester Crown Court that Baby K was born prematurely at 25 weeks in February 2016 at the hospital, and had been connected to a ventilator and other machines monitoring her heart rate and oxygen levels.

Little more than an hour after the birth, while other staff were absent, Johnson said, senior doctor, Ravi Jayaram, entered the room where she was being looked after to find the baby's breathing tube dislodged, alarms that should have sounded had become disabled, and Letby standing there "doing nothing".

Johnson added that on two further occasions that night, Letby interfered with the breathing tube to give the impression there was a particular problem with the baby.

"These were the actions of a cold-blooded, calculated killer," Senior Crown Prosecutor Nicola Wyn Williams said in a statement on Tuesday following the verdict.

Baby K died in a different hospital three days later, although the prosecution said this had nothing to do with the allegation against Letby.

Letby's sinister follow-up.

Two years later, in April 2018, Letby searched for Baby K's surname on Facebook, as revealed in court. Prosecutor Nick Johnson KC described this as a pattern of behaviour, informing the jury:

"The truth is that Lucy Letby had a fascination with the babies she had murdered and attempted to murder, and with their families.

"She took pleasure in her murderous handiwork."

In her evidence, Letby again denied having ever harmed any baby put in her care, and said she had no recollection of the night in question.

Her defence lawyer said the evidence was not there to prove her guilt.

Letby showed no reaction in the court dock as the jury delivered their unanimous verdict. Baby K’s father buried his face in his hands, while the child’s family wept in the public gallery.

Baby K's family respond.

Image: Getty

"Justice has been served and a nurse who should have been caring for our daughter has been found guilty of harming her," the family said in a statement read outside court by police.

"But this justice will not take away the extreme hurt, anger and distress that we have all had to experience."

Det Ch Insp Nicola Evans, of Cheshire Police said the parents of the young child were the pinnacle of resilience and courage, despite having to face "continual denials" from Letby.

"I would like to thank them for continuing to put their faith in us and I hope that the conclusion today provides them with some peace of mind and some of the answers they have been searching for," she said.

"Once again, there are no winners in this case. Today is not a time for celebration – it is a time for reflection and a time for the family of Baby K."

Letby's existing charges.

This new guilty verdict will add to Letby's existing criminal record.

Letby was originally found guilty of killing the five baby boys and two baby girls by injecting the infants with insulin or air, or force-feeding them milk.

The case shocked the UK and prompted the government to order an inquiry into why concerns about her behaviour had not been heeded by hospital bosses.

Police also said they were carrying out further investigations into whether there were other victims at hospitals where Letby had previously worked.

On social media, some have questioned the rulings. Ahead of the latest trial, the New Yorker magazine ran an article questioning the evidence against her.

In May, however, England's Court of Appeal rejected her attempt to overturn her conviction, which had been mainly based on arguments that evidence from the prosecution's expert witness was flawed.

Letby had also argued jurors were wrongly told they did not have to be sure how she was alleged to have killed or attempted to kill her victims.

But Judge Victoria Sharp said in a ruling made public on Tuesday, that "it was not necessary for the prosecution to prove the precise manner in which she had acted".

Letby will be sentenced for the attempted murder of Baby K on July 5.

- with AAP.

Feature image: Getty.