An increasingly prevalent feature of high schools in the US is the requirement that students wear identification cards at all times while on school property. The measure has just been introduced in Pattonville High School in St Louis, where students and school staff are required to wear the ID badges.

Leonard Sullivan, a teacher at the school for more than 30 years, says the scheme is a good idea: "It's easier to get to know students you don't have in class and for them to get to know your name." Staff and pupils say that knowing who people are helps to make a school feel safer.