In my conversation with your reporter, I stressed the speculative nature of this theme. For virtually all of the possible explanations of the suggested "textbook discrimination" I referred her to the extremely interesting work started by David Lambert at the London University Institute of Education. I also made it clear that the Keele work has been carried out by my colleague Michael Johnson and that he, not I, is the authoritative source of further comment and interpretation.
I apologise if this appears to be a bit pedantic, but the "ifs" and "buts" of research are rather important, as are acknowledgments of the work of fellow researchers.
Professor Margaret Maden Keele University, Staffordshire