Lynsey Artell gave birth to her son Asa in March 2016 as Letby was attacking babies and stalking the corridors of the neonatal unit at the Countess of Chester Hospital.

Letby has been found guilty of murdering seven babies and attempting to murder six other infants.

Ms Artell says she and her husband were discussing how their premature son was making good progress on the unit when the couple noticed Letby eavesdropping on their conversation.

She says, out of the blue, Letby told them: "I don't like parents getting their hopes up because we never know what could happen at this stage."

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Ms Artell, who was a former nursing assistant at the hospital and had suffered numerous miscarriages, made a complaint to senior staff on the ward.

Speaking exclusively to Sky News, she said: "As a parent, I absolutely erupted and was furious. How dare you take that hope away from me?

"This was my seventh pregnancy... she needed to know that that was inappropriate."

Ms Artell now fears her actions could have prompted Letby to attack little Asa as he lay helpless in his ventilator.

The next day, the mother briefly left her two-day-old son's bedside to get a coffee. When she returned, nurses and doctors were gathered around him, drawing the screens.

He'd had a huge spike in his insulin levels and was receiving urgent treatment.

During her trial, the court heard one of Letby's favoured methods of attack was injecting her tiny victims with insulin.

The new mother watched as medics worked on her son.

"I just thought I don't want to lose another one," she said. "I hadn't even held him yet."

Mercifully, doctors managed to bring Asa back around, and eventually he was discharged from hospital.

Chilling conversations of Letby's suspicious colleagues

Ms Artell had concerns and still has not received a satisfactory answer into why her son's insulin levels shot up with no warning.

After Letby was arrested, Ms Artell contacted police who investigated twice but did not bring charges in relation to Asa.

"I would have liked them to have spoken to us," she said.

"It's frustrating… because they haven't got the whole facts. You think 'oh my god, I was so close'."

Having worked at the Countess of Chester Hospital, she also recalls chilling conversations from suspicious colleagues when there was a medical emergency.

She said: "When alarms would go off, during the night especially, there would be a phrase that people would use, colleagues that I know. They would say: 'I wonder if Lucy's working tonight?'."

Following the verdicts, Ms Artell now hopes police will reinvestigate her case and others, and that more charges may be brought.

She also wants a public inquiry so lessons can be learned, and Letby's horrific crimes can never be repeated.

"A guilty verdict is brilliant for some people, they get justice," Ms Artell said.

"It doesn't bring anyone back, but it gives some people some answers. But it also leaves many people who haven't had answers, like me."

Read more:
More families told their children could be victims
Inside court and the trial of a baby killer
Parents of boys Letby tried to kill criticise hospital
Video shows moment of Letby arrest

Detective Superintendent Paul Hughes, of Cheshire Police, told Sky News: "We're obviously committed to looking at the entire time that Lucy has been employed as a nurse, whether it's at the unit at the Countess of Chester Hospital or the Liverpool Women's Hospital.

"That's to make sure that at the end of Operation Hummingbird we can say, with a degree of confidence, that we've investigated every baby who has been in the neonatal unit and we're confident that there are, or are not, further cases."

How the police caught Lucy Letby

Sky News has contacted the Countess of Chester Hospital for comment on Ms Artell's son.

The hospital earlier commented on the Letby verdict, saying it was "deeply saddened and appalled".

Dr Nigel Scawn, medical director of Countess of Chester Hospital, said: "We are extremely sorry that these crimes were committed at our hospital and our thoughts continue to be with all the families and loved ones of the babies who came to harm or died. We cannot begin to understand what they have been through.

"This case has had a profound impact on our patients and our local community and also our staff who come to work every day determined to provide safe and high-quality care for all of our patients.

"Our staff are devastated by what has happened and we are committed to ensuring that lessons continue to be learned.

"We are grateful for the co-operation of our staff especially those who have maintained the utmost professionalism whilst giving evidence in this trial, sometimes on multiple occasions.

"Since Lucy Letby worked at our hospital, we have made significant changes to our services and I want to provide reassurance to every patient that may access our services that they can have confidence in the care that they will receive.

"Finally and most importantly our thoughts are with all the families and loved ones at this very difficult time."