This article explores the effectiveness of a mathematics subject knowledge development model that integrates conventional text-based distance learning with an e-learning coaching and peer group conferencing environment. The effectiveness of the model in supporting 194 trainee primary (pupil's aged 5-11 years) teachers achievement of the subject knowledge standards required for qualified teacher status is evaluated and the impact of the model on trainee confidence is explored. Features of the model that trainees, tutors and post-qualifying teachers identify as critical factors for success are outlined and the relevance of the model for teacher professional development is discussed. (Contains 2 figures and 8 tables.)