Training and practice within British clinical psychology are profoundly influenced by the belief that behavioural psychotherapy has been shown as more effective than verbal psychotherapy in the treatment of disorders for which both claim utility. A review of the comparative outcome evidence shows that this belief is largely unfounded. Taken together with the growing theoretical convergence between verbal and behavioural approaches, this negative result from comparative outcome studies has important implications for the future development of psychotherapy research, training and practice. More precise and sophisticated research strategies are required to identify the therapeutic ingredients of the psychotherapies, whether these be common to many approaches or specific to particular treatment modes. Closer integration between clinical and research activities in all forms of psychotherapy is necessary. Clinical psychologists should be trained in a variety of behavioural and verbal methods, and in the research methodologies necessary to evaluate and develop these methods. If the challenge of the present state of evidence is not evaded, then we may eventually supersede crude global comparisons, with precise specification of interventions appropriate for given populations.