Abstract
Externally imposed educational change is generally perceived with trepidation by teachers, as it can alter their practice to a greater or lesser extent, involve learning new skills and spending more time on routine tasks. This paper explores the effects of the top-down initiative of the National Numeracy Strategy (NNS) on a group of primary trainee teachers in England, and is based on the findings of an empirical study in which the data were gathered through in-depth interviewing. It is suggested that the student teachers see the NNS as a helpful framework for developing their professional expertise in an area where they often have experienced some anxiety. The ways in which the NNS has impacted on the trainees' understanding of their task as teachers of mathematics in a primary school are also examined.