Patrick Nash, head of the Teacher Support Network, said his helpline staff had already taken late-night calls from badly shaken teachers. The network has produced counselling guidance.
"A lot of London schools will have been directly affected by this," Mr Nash said.
"Our concern is to make sure people are aware of some of the simple things you need to do when you have been in a shocking situation."
These include talking about the experience, resting, and avoiding watching too much media coverage. Schools should consider discussing the bombings at assemblies, the group advises. Mr Nash said: "Watch out for kids who are withdrawn. Those are the ones who are internalising shock."
* The Teacher Support Network's helpline is 0800 0562 561.Reuse content