It is a fundamental weakness of our educational system that we use students’ age to determine both professional status and funding (“Education budgets”, By the numbers, 18 October). But a simple formula based on the child’s age plus 10 would focus minds and transform the system. Five-year-olds would be in classes of 15, 11-year-olds in classes of 21 and 18-year-olds in classes of 28, which might be a good preparation for university lecture halls that hold 100.

David Hanson, Chief executive, Independent Association of Prep Schools.