Last term I invigilated a reading examination at a fee-paying prep school where I work as a supply teacher. About five minutes in, a little girl called Maisie raised her hand. She looked downcast. ‘Yes Maisie?’ She pointed, unspeaking, at the first question. ‘Shall I read it to you?’ She nodded. I read it. ‘Does that make sense?’ She shook her head. ‘Well,’ I began, stalling, as I tried to work out which bit was confusing for her, ‘why don’t you have another look at the text? The answers will be there in the story.’ She mumbled something. ‘What’s that?’ She mumbled again, and this time I heard her: ‘I can’t read.’ Maisie is nine. She has been at this school since she was five. Her teachers, I later discovered, all know she can’t read.