Conjoined twins were born with one of them having no proper heart or lungs. One of the twins was being kept alive by the other twin whose heart circulated blood for both of them. The Doctors wanted to operate to separate the twins. This would result in the weaker twin dying. The parents would not consent to this. The Doctors claimed that it was lawful to operate. The Court of Appeal gave the declaration. In the judgement, one of the points considered was the doctrine of necessity.