A mother and her new boyfriend are accused of the murder and sexual assault of a toddler who suffered 21 broken bones in the weeks leading up to her death, a court heard. Isabelle Welsh, two, collapsed at her home in Hartington Close, Thornaby, Teesside, having suffered a “massive head injury”, and could not be saved, jurors were told. Her mother, Alexandra Walker, 25, and Harrison Simpson, 22, deny murder, allowing the death of a child, sexual assault and child cruelty and are on trial at