By Adam Hawksbee Free school meals and supervised tooth brushing sound appealing but Britain will come to regret eroding the norm of parental responsibility, writes Adam Hawksbee Sadiq Khan rarely receives positive headlines, so the mayor will have been delighted with recent praise for his commitment to universal free school meals. A new study finds that when all kids get a free lunch from primary schools it cuts obesity, improves attainment and reduces stigma for poorer pupils. What’s not to like? But there’s a problem with this brand of “evidence-based policy”. Studies looking at government …