What is the new challenge to the evidence used to convict Lucy Letby?

Letby's legal team is preparing to submit a case to the body that investigates potential miscarriages of justice

The evidence used to convict Lucy Letby was challenged on Tuesday by an international panel of experts, which concluded there was no proof the nurse had murdered or harmed any of the babies.

Letby, 35, is serving 15 whole-life prison terms after being convicted of murdering seven babies and attempting to kill another seven at the Countess of Chester hospital in north-west England in the year to June 2016.