Bell was sentenced to life in prison. In point of fact, she was imprisoned till she was 21 and then released on probation for life. That she has achieved some measure of functional life was due largely to the dedicated efforts of a few helpers here and there and her own inner resources, rather than the system. She could have very easily fallen into a life of repeated crime. Sereny does not oppose punishment for such children, but it should not be punishment for its own sake.
Attention has to be paid to helping re-habilitate the person as well.
She shows very well how the English system routinely fails troubled children like Mary Bell. A child like Bell should have been in a secure facility that could address her severe emotional problems, yet such places are few and far between. No one seems to know what to do about the problem of juvenile crime. In America, virtually no one who has wondered about the Colorado school killers seems to have looked to their family lives. The same was true for Mary Bell, who was branded as a monstrous incarnation of evil then and now.