The serial killer nurse Lucy Letby will never be released from prison after a judge sentenced her to a rare whole-life term for the “sadistic” murder of seven babies.

Letby, 33, is only the third woman alive to be given the jail term in the UK. She was sentenced at Manchester crown court on Monday.

The former neonatal nurse, the worst child serial killer in modern British history, was also convicted of attempting to murder six more babies at the Countess of Chester hospital.

Sentencing Letby, Mr Justice Goss said: “This was a cruel, calculated, and cynical campaign of child murder involving the smallest and most vulnerable of children, knowing that your actions were causing significant physical suffering and would cause untold mental suffering.

“There was a deep malevolence bordering on sadism in your actions.”

The judge said she “acted in a way that was completely contrary to the normal human instincts of nurturing and caring for babies”. Goss added that her claims to have done her best in caring for babies was “one of many lies” she told throughout the trial.

He said: “There is no doubt that you are intelligent and outwardly were a very conscientious, hardworking, knowledgable nurse – which enabled you to harm babies for some time.”

Letby had a “detached enthusiasm” for the resuscitation of babies fighting for life, the judge said, adding that she “cruelly and callously” made inappropriate remarks to parents or colleagues during or after a death.

She kept hundreds of medical documents as “morbid records of the dreadful events surrounding your victims and what you had done to them”, the court heard.

Goss said it was not for him to “reach conclusions about the underlying reasons” for Letby’s actions. “Nor could I,” he added. “For they are known only to you.”

Letby refused to be present in court for the sentencing, in which parents of her victims described in powerful detail the impact of her crimes. Goss ordered her to be provided with a copy of the sentencing remarks and of the victim impact statements in her absence.

In one statement, the mother of a baby murdered on his fourth day alive, Child C, said she felt it was like watching someone else’s life as her son died.

Holding back tears in court, she said: “The trauma of us all will live with us all until we die. Learning that his killer was watching us [as we grieved] is like something out of a horror story.”

She said she would “live forever with the guilt” that she was not able to protect him: “I think about what his voice would have sounded like. What he would have looked like now. Who he would have been.”

More details soon …