This paper outlines the development of a formulation tool for use in child psychotherapy practice. This was developed in response to Child Protection legislation and practice, which was shown to be different across the four nations of the United Kingdom, and details a National Practice Model that is part of Scottish Government Legislation. The paper discusses the way that child psychotherapy can make a unique contribution in the treatment of a child, showing positive progressions in child well-being and in the functional aspects of a child’s personality development. The paper uses a detailed case example to demonstrate the use of the formulation tool under discussion. The author suggests that a structured approach allows the child psychotherapist to make best use of their whole training and observational skills, as required by each case.