Let me tell you a true story. A few years ago, I worked in a very smart school where everyone had to follow the dress code very carefully. If female teachers wore sleeveless dresses, they had to wear a cardigan or blazer over the top. One summer day, the temperature went above 30°C. The classrooms felt like saunas, and the playground was so hot that just standing outside made you feel unwell. There was hardly any shade anywhere. In the morning, the headteacher sent a message