Prosecutors have admitted that evidence heard in court detailing what time staff entered and left the unit where Lucy Letby worked was incorrect.
It comes after Letby, 34, received 14 whole-life prison sentences for murdering seven babies and attempting to kill six more.
She became the worst child serial killer in British history for crimes committed while she worked at the Countess of Chester hospital.
And after a retrial at Manchester Crown Court last month, Letby was found guilty of trying to kill another child, known only as Baby K.
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