New Delhi: A nurse in a British hospital will spend the rest of her life behind bars, a judge ordered on Monday following her conviction for murdering seven newborn babies and trying to kill another six. The 33-year-old murdered five baby boys and two baby girls at the neonatal unit of Countess of Chester Hospital in northern England where she was working in 2015 and 2016.

"This was a cruel calculated and cynical campaign of child murder involving the smallest and most vulnerable of children," said the judge, James Goss, who sentenced her to life imprisonment with no prospect of release.

"There was a deep malevolence bordering on sadism in your actions... You have no remorse. There are no mitigating factors," he added.

Lucy Letby's motives remain unclear, but the scale of her crimes points to intricate planning. She deliberately harmed the babies in various ways, including by injecting air into their bloodstreams and administering air or milk into their stomachs via nasogastric tubes.

She also poisoned infants by adding insulin to intravenous feeds and interfering with breathing tubes. She was finally removed from frontline duties in late June of 2016 and was arrested at her home in July 2018.

Lucy Letby is the only child

Born in Hereford -- a city in west-central England -- on January 4, 1990, Lucy Letby is reportedly the only child of John and Susan Letby, a retail boss and accounts clerk who are now both retired. She qualified as a children's nurse at the University of Chester in 2011.

Letby completed training placements at Liverpool Women's Hospital before joining the neonatal unit at the Countess of Chester Hospital in January 2012.

Lucy Letby is most prolific child serial killer in modern UK history

Lucy Letby, who was in her 20s at the time of the murders, is said to be the most prolific child serial killer in modern British history.

During her 10-month trial, prosecutors said the hospital in 2015 started to experience a significant rise in the number of babies who were dying or suffering sudden deteriorations in their health for no apparent reason. Some suffered 'serious catastrophic collapses' but survived after help from medical staff.

Letby was on duty in all the cases with prosecutors describing her as a 'constant malevolent presence' in the neonatal unit when the children collapsed or died. They said the nurse harmed the babies in ways that did not leave much of a trace, and that she persuaded her colleagues that the collapses and deaths were normal.

Police then launched an investigation into the baby deaths at the hospital in May 2017 and Letby was eventually charged in November 2020.

Child serial killer Lucy Letby proclaimed her innocence

Lucy Letby testified for 14 days, proclaiming her innocence.

During the trial, the defense argued that she was a 'hard-working, dedicated and caring' nurse who loved her job and that the infants' sudden collapses and deaths could have been due to natural causes, or in combination with other factors such as staffing shortages at the hospital or failure by others to provide appropriate care.