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 worked so much overtime that her manager was not suspicious when babies died on her watch, the Thirlwall Inquiry has heard.

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.

The neo-natal nurse made the mistake in July 2013, when she administered ten times the correct dose to the infant via an intravenous drip at the end of a night shift.

The Thirlwall Inquiry into the events surrounding Letby’s crimes at the Countess of Chester Hospital was told Letby and another nurse had set up the morphine infusion for the youngster. Letby’s colleague was said to be so “distraught” about the incident that she almost resigned,

Lucy Letby gave a potentially fatal dose of morphine to a newborn baby two years before she murdered her first victim, an inquiry has heard. The infant received 10 times the correct amount of the painkiller at the end of a night shift in July 2013 and could have died if colleagues at handover had not spotted the error an hour later.