I conclude that on the evidence it was open to the jury to find that a relationship of schoolmaster and pupil, and with it a resultant duty of care, came into existence well before 9.00 a.m. on the morning in question. The defendant headmaster had, from the best of motives, permitted, although not encouraged, pupils to come to the school as early as 8.15 a.m. The school gates were open from that hour onwards and the classrooms were apparently open well before 9.00 a.m. The headmaster knew that in fact large numbers of children made use of the school between 8.15 a.m. and 9.00 a.m. on school days; perhaps up to two hundred children, almost half the total attendance at the school, would be found there before 9.00 a.m. Knowing of their presence the headmaster naturally enough asserted his authority over them. He required them, he said, until 9.00 a.m. "to sit down in the playground and talk or read, study, something like this"; he had expressly forbade them to play games in the school grounds before 9.00 a.m. and he said that as often as once a week he observed the children obeying these directions of his. He had instructed teachers who might be passing through the school playground before 9.00 a.m. to ensure that these directions were obeyed. In addition he would keep an eye on the children as they passed outside his office, as would other teachers as children passed the teachers' staff room. Because of this and because he believed that his instructions were being obeyed, the children being of "good behaviour", he thought there was no need for regular supervision of the children who arrived at school before 9.00 a.m.