It is to be expected that the "slavish use" of any materials will have an adverse effect. Those of us who originally formed the Teacher Learning Community that was SMILE (secondary mathematics independent learning experience) wrote the earliest of those materials because we needed suitable activities for the mixed-ability groups for whose maths education we were responsible. However, we had no illusions that those materials would stand on their own. We were not abdicating our responsibilities, first, to assess the mathematical position, progress and preferences of each pupil, and then to prescribe accordingly and monitor closely, with frequent interventions, the future mathematical journey of every member of the class.
The DfES has been obsessed for many years with the preparation of materials for maths teachers to use, but at the expense of preparing the teachers themselves to make accurate assessments and devise their own materials to guide pupils along appropriate learning paths. Any classroom materials are only as good as the teacher who uses them.
Rachel Gibbons. 3 Britannia Road, London