This paper describes a case study concerning a student teacher at risk of failing a teaching placement, who was supported by colleagues and university tutors through the use of a diagnostic tool in the form of a checklist. The checklist comprised a number of categories relating to aspects of teaching and learning within the classroom and was used consistently by staff to provide feedback to the student and as a basis for discussion and evaluation of his lessons. Scrutiny of the checklists, completed over a four week period, staff questionnaires and staff and student interviews indicate that the student and teaching staff found the tool user friendly and helpful in identifying areas of good practice and those requiring development. Other benefits for the student included the development of a pro-active approach to planning lessons and reflection on practice. The tool may be useful as a means of providing formative feedback and initiating dialogue relating to practice, particularly at an early stage of a teaching career.