Nurse Lucy Letby was “faffing and not doing anything” while a premature baby boy she murdered was covered in blood, the baby’s mother has said.

Letby, 33, was convicted on Friday of murdering seven babies and attempting to murder six more while working at the Countess of Chester Hospital between 2015 and 2016.

The parents of Child E, a twin boy who was born prematurely in 2015, said they thought they were “in safe hands” when they left their son alone with Letby on an intensive care ward.

The boy’s mother told Letby’s trial at Manchester Crown Court the nurse was trusted “completely” with the care of their son.

However, the nurse injected air into his bloodstream and deliberately caused him to bleed.

When his parents returned a short while later they found their son was “dangerously ill” and doctors trying to save him, before being told there was nothing they could do.

His mother, who cannot be named for legal reasons, was taking milk to her twins when she heard one of her sons crying loudly.

She told the BBC: “The crying, I had never heard anything like it since.

“It was screaming, it was screaming and I was like ‘what is the matter with him?’

“He had blood round his mouth and Lucy was there, but faffing about, not doing anything.

“Lucy said ‘don’t worry’ (and that the) registrar was coming and she told me to go back to the ward.”

Letby told her a feeding tube had irritated the back of his throat and caused bleeding, the trial heard.

The baby’s mother left him in an intensive care area and went to call her husband, thinking their son was in safe hands, but had to return soon after when his condition became critical.

During the trial, prosecutor Nick Johnson KC asked her: “Did you do what you were told?”

Child E’s mother replied: “Yes, because she was an authority and she knew better than me and I trusted her. Completely.

“She said the registrar was on the way and if it was a problem someone would ring up to the post-natal ward.

“The rules were go back upstairs and if there was a problem I would call you, and that was Lucy Letby on the neo-natal unit. I followed those rules.”

She later cried as she told jurors: “I knew. I knew there was something wrong and I had known from leaving him, but I left.”

She told the broadcaster: “We were taken in and we were told to talk to him and hold his hand, and then the conversation with the consultant, who said ‘we’re going to stop, it’s not helping, we want him to die in your arms’. ”

After the infant died she was asked if she wanted to bathe the baby, as part of the standard bereavement service offered to parents.

She told the trial: “At that time I didn’t feel like I was able to. I was just broken and I couldn’t, so Lucy Letby bathed him in front of me.”

She broke down in tears as she added: “After he was bathed he was placed in a white gown. I just remember being thankful because we had no clothes for him because he was so little.”

Letby was also found guilty of attempting to murder the boy’s twin brother, Child F, who was poisoned with insulin.

Letby later presented her with a photograph of Child F holding his twin brother’s teddy, she told the court.

She added: “She said ‘I got this picture. He rolled over and hugged his bear. I thought it was so amazing I took a picture for you’.”