Lucy Letby gave a potentially fatal dose of morphine to a newborn two years before babies began dying unexpectedly at the Countess of Chester Hospital, the Thirlwall Inquiry has heard.

Lucy Letby's exchanges with fellow nurses and doctors at the Countess of Chester Hospital during her year-long killing spree have been exposed in the Thirlwall Inquiry

Lucy Letby gave a baby 10 times the prescribed dose of morphine "in error" two years before her killing spree began, a public inquiry has heard. The nurse was then unhappy at being told she could no longer administer controlled drugs at the Countess of Chester Hospital after the incident in July 2013.

Lucy Letby was convicted of killing seven babies and attempting to murder yet another seven before she was charged and sentenced to serve a life sentence in prison