A former neonatal nurse convicted of murdering seven babies in her care and trying to kill six others at a hospital in northern England was sentenced Monday to life in prison with no chance of release by a judge who highlighted "the cruelty and calculation" of her actions.

Lucy Letby, who refused to appear in court to face her sentencing or to hear grieving parents share their anger and anguish, was given the most severe punishment possible under British law, which does not allow the death penalty.

Justice James Goss said the number of killings and attempts and the nature of the murders by a nurse entrusted with caring for the most fragile infants provided the "exceptional circumstances" required to impose a rare "whole-life order."

"There was a malevolence bordering on sadism in your action," Goss said, addressing the absent defendant. "During the course of this trial, you have coldly denied any responsibility for your wrongdoing. You have no remorse. There are no mitigating factors."

A Manchester Crown Court jury that deliberated 22 days convicted Letby, 33, of murdering the seven babies over a yearlong period that saw her prey on the vulnerabilities of sick newborns and their anxious parents.

The victims, who were given anonymity and listed only by letters, such as Child A and Child B, died in the neonatal unit at the Countess of Chester Hospital in northwest England between June 2015 and June 2016.

"I don't think we will ever get over the fact that our daughter was tortured till she had no fight left in her and everything she went through over her short life was deliberately done by someone who was supposed to protect her and help her come home where she belonged," the mother of a girl identified as Child I said in a statement read in court.

Prosecutor Nicholas Johnson said Letby deserved a "whole-life tariff" for "sadistic conduct" and premeditated crimes.

Defense lawyer Ben Myers said Letby maintained her innocence and that there was nothing he could add that would be able to reduce her sentence.

Some families suffered multiple tragedies, as Letby targeted three sets of twins and a set of triplets.

A mother of twins was left to grieve the loss of a son and blame herself when her family — vigilant to watch over the second infant after the first one's death — let their guard down and Letby struck again, harming the boy's sister, who survived.

"Little did we know you were waiting for us to leave so you could attack the one thing that gave us a reason to carry on in life," the mother said.

The parents of triplets lost two of their babies, and the third survived after being transferred to another hospital. The couple said in a video played in court that Letby had ruined their lives.

"The anger and the hatred I have towards her will never go away," the father said. "It has destroyed me as a man and as a father."

One father called Letby "the devil" and said she had tried to kill his daughter twice. The nurse didn't succeed but the girl was left blind, with brain damage and having to be fed through a tube.

"Every day I would sit there and pray. I would pray for God to save her," the father of Child G said. "He did. He saved her, but the devil found her."

Letby's absence, which is allowed in British courts during sentencing, fueled anger from the families of the victims, who wanted her to listen to statements about the devastation caused by her crimes.

Politicians and victim advocates have called for changes in the law to force criminals to appear for sentencing after several high-profile convicts chose not to face their victims in recent months.

Prime Minister Rishi Sunak, who called the crimes "shocking and harrowing," said his government would bring forward in "due course" its plan to require convicts to attend their sentencings.

"It's cowardly that people who commit such horrendous crimes do not face their victims and hear first-hand the impact that their crimes have had on them and their families and loved ones," Sunak said.

An independent inquiry will be conducted into what happened at the hospital and how staff and management responded to the spike in deaths. However, there are calls for a more formal inquiry led by a judge who could order people to testify.

During Letby's 10-month trial, prosecutors said that in 2015 the hospital started to see a significant rise in the number of babies who were dying or suffering sudden declines in their health for no apparent reason.

Some suffered "serious catastrophic collapses" but survived after getting help from medical personnel.

Letby was on duty in all of the cases, with prosecutors describing her as a "constant malevolent presence" in the neonatal unit when the children experienced medical distress or died. The nurse harmed babies in ways that were difficult to detect, and she persuaded colleagues that their collapses and deaths were normal, they said.

Senior doctors said over the weekend that they had raised concerns about Letby as early as October 2015 and that children might have been saved if managers had taken their concerns seriously.

Dr. Stephen Brearey, the head consultant at the Countess of Chester Hospital's neonatal unit, told the Guardian newspaper that deaths could arguably have been avoided as early as February 2016 if executives had "responded appropriately" to an urgent meeting request from concerned doctors.

Letby was finally removed from front-line duties in late June 2016. She was arrested at her home in July 2018.

After Letby was arrested, police found a note in her home that served as a chilling confession: "I killed them on purpose because I'm not good enough to care for them," she wrote. "I am a horrible evil person."

The mother of Child C wept on the witness stand as she spoke of the loss of her firstborn, a "feisty" and "defenseless baby boy."

She had worn her son's hand and foot prints around her neck to remember him. The later realization that the person who took those prints — Letby — was the same person who took his life tainted the memory, she said.

"There is no sentence that will ever compare to the excruciating agony that we have suffered as a consequence of your actions," she said. "At least now there is no debate that, in your own words, you killed them on purpose. You are evil. You did this."