Gillian Tett:

Last week, my daughters experienced a very modern American childhood ritual. The teachers at their Manhattan school suddenly locked the classroom door and told everyone to hide under their desks, or inside the cupboard. Then somebody walked along the corridor outside, banging on the doors in a menacing manner, shouting, “Let me in.”

The teacher kept the door shut and told the children to silently crouch down, as part of a so-called Code Red drill. “It was very scary,” one of my daughters observed. “But this is what we have to do if a stranger comes into school.”

Welcome to one of the quirks of America in 2014. When I was a child at a British school 30 years ago, I often took part in fire drills, to prepare for the remote risk of a fire. But these days, American schools are not just conducting fire evacuations. In the wake of recent attacks on educational establishments – such as the tragic shootings in Newtown, Connecticut in late 2012, or the attacks on a California college last week – they are actively drilling children on how to respond to violent attacks as well.

These drills vary across the country. In some American schools, teachers have decided that they want “realistic” drills, so children huddle in places such as the gym while somebody fires a blank gun. In other establishments, teachers keep the threat relatively vague. Meanwhile, in the trendier parts of Brooklyn, the schools are so worried about psychological distress that they offer counselling to pupils after the drills.