The School Certificate passed, the system allowed him a small part to play, that of the 'maths brain'. There was no mathematical sixth at Sherborne, as at some schools, notably Winchester. There was a science sixth for whom mathematics, Alan's best subject, was regarded as subsidiary. Nor was Alan promoted to the sixth form immediately; he was held back in the fifth for the autumn of 1928, but allowed to join the sixth form for their mathematics classes. These were taught by a young master, Eperson, just a year down from Oxford and a gentle, cultured person, the kind of master who would constantly be played up by the boys. Here was the chance for the system to redeem itself at last, the spirit breaking through the letter of the law. And in a negative way, Eperson did what Alan wanted, by leaving him alone:21

All that I can claim is that my deliberate policy of leaving him largely to his own devices and standing by to assist when necessary, allowed his natural mathematical genius to progress uninhibited …

He found that Alan always preferred his own methods to those supplied by the text book, and indeed Alan had gone his own way all the time, making few concessions to the school system. During the machinations over the School Certificate, or even before, he had been studying the theory of relativity from Einstein's own popular account.22 This employed only elementary mathematics, but gave full rein to ideas which went far beyond anything in the school syllabus. For if Natural Wonders had introduced him to the post-Darwinian world, Einstein took him into the twentieth century revolution of physics. Alan produced a small red Memo Book of notes, which he gave to his mother.