Jane’s School Safety Handbook has proved popular in the US, since September 11, and the company is giving serious consideration to publishing a UK version.

It may seem a huge leap from war plans to warring pupils, but high-profile shootings, not only in the US but more recently in Germany, have highlighted the need for schools to have procedures in place for unexpected security alerts.

The handbook offers guidance on crisis planning, response and recovery, and identifying early warning signs - including the characteristics of violent youth.

Teachers should keep their eye on students who have:

* a history of uncontrolled anger; l previously threatened violence;

* few friends and are socially withdrawn and isolated;

* little parental support;

* previously brought weapons to school;

* a history of exclusions and truancy.

However, research by the US Secret Service, the FBI and other agencies suggests that “there is no foolproof way to identify the next school shooter”. Attackers have been both bullies and victims, academically successful and educational failures, notes the guide.

It recommends that schools invest in prevention, looking for early warning signs of bullying or isolation, name-calling or threats, and resolving disputes between students. Disturbingly most of the killers had developed their plans at least two weeks in advance, and nearly three-quarters had told someone else about them.

There are sample letters to parents covering terrorist attacks and student fatalities, and case studies on high-profile incidents such as the loss of 16 pupils and their teachers in Dunblane six years ago.

Jane’s spokesman Mike Foster said: “Defence increasingly is relating not to tanks and armies but institutions, buildings and homes.”