Issues of religion and the right to free speech have become urgent, and schools need to think about how best to address them. One of the most balanced treatments in the immediate aftermath of the London bombings was done by CBBC's excellent Newsround, which carried an interview with BBC journalist Frank Gardner, himself a victim of terrorism, alerting children to the threat without frightening them.
The current crisis provoked by the Danish cartoons shows the serious consequences that can follow from misjudging how to deal with issues of terrorism and religion. The cartoons have only appeared on websites in this country and have not been published in the press: this raises important questions about how far the right to free speech justifies the giving of religious offence.
The issue is complicated because one of the cartoons links the Prophet Muhammed directly with terrorism. The conviction of the Muslim cleric Abu Hamza for stirring up racial hatred and the discovery of an arsenal of terrorist equipment in the basement of the Finsbury Park mosque means that many people, including children, are likely to make a similar sort of connection to the one the cartoonist drew.
How do you approach these issues in the classroom if you have no specialist knowledge? Terrorism can feature in a wide range of subjects - history, English, RE, citizenship and PSE - and might well feature in a school assembly, especially in the aftermath of an atrocity. The term is widely used, and often used wrongly. Let's start with some definitions.
What is terrorism?
The world's leaders at the recent UN summit on terrorism failed to agree a definition, but don't let that stop you: this is vital. It is true that one person's terrorist is another's freedom-fighter, but that doesn't mean that defining terrorism is entirely a matter of opinion.
Terrorism is not primarily about letting off bombs or guns: it is about exercising control. An assassin is trying to kill a particular individual, but terrorists' true targets are not the people they kill, but the people they leave behind. The idea is that they will be so terrified by thinking it could be their turn next, that they will bend to the terrorists'
The IRA bombers didn't want to blow up Harrods or let off bombs in Belfast; they wanted a united Ireland, and terrorising people, they hoped, would put so much pressure on governments that they would get it. But governments can - and do - do the same. A terrorist state is not just one which finances terrorist groups, it's one which uses terror to control its own people.
But how can blowing up a train achieve anything?
On its own, it can't, but if it is part of a never-ending and unpredictable pattern, then it suggests that the authorities can no longer guarantee people's safety. In extreme cases, as happened in areas of Londonderry in the 1970s, it can mean the creation of "No-Go" areas, where the terrorists literally control the streets. Terrorism can lead people to lose confidence in their government, as when the Spanish people felt the government was covering up its own incompetence after the Madrid bombings and voted it out of office. Our own government's denial of any link between the London bombings and the war in Iraq met a similarly cynical reaction.
Why do people become terrorists?
It is a sad fact that in the right circumstances almost anyone can become a terrorist, and that includes the nicest, most studious children in your class - and it includes you. The motive might be patriotism: resistance fighters during the Second World War aimed to spread terror among the Germans and their collaborators, and almost exactly the same tactics are being used against coalition forces in Iraq today.
But often the spur can come from the usual hazards of being caught up in a war zone: having your house searched by angry soldiers, or a friend or relative killed in crossfire. And, as recent news reports have shown, people can be turned to terrorism by rhetoric and preaching from those determined to instill fear and hate. Most terrorists are made, not born.
Can terrorists win?
There's no simple "lesson of history" here. Terrorists have certainly brought governments to a negotiating table they would otherwise have avoided: the IRA forced the British to set up an independent Ireland in 1922, though they have never succeeded in bringing Northern Ireland into it. Jewish terrorist groups forced the British to withdraw from Palestine in 1947, and the Hamas terrorists did much the same to the Israelis after they invaded Lebanon in 1982.
But there are plenty of examples of terrorist movements that have failed completely: the Italian Red Brigade and the German Baader-Meinhof gang never achieved the revolution they fought for.
How can someone who believes in God become a terrorist?
Pope John Paul II pleaded "on my knees" with the Catholics of Ireland to renounce violence, but they took no notice. This is a question that needs to be aired in class, but the answer probably lies initially in working out what sort of a God the terrorist believes in. Many Muslim scholars point out that current terrorist campaigns do not qualify as jihad (holy war), and that jihad was not part of the original tenets of Islam anyway (Islam means "surrender" - to the will of God - so "militant Islam" means "militant surrender", a strange contradiction in terms).
In the Gospels, Jesus never allowed himself to be drawn into resistance fighting against the Romans, though there was great pressure on him to do so. It's certainly true that terrorists frequently claim to be fighting for religious reasons, and their voices tend to swamp those of more moderate and peaceful religious groups who disown them.
None of the major religions which are claimed by terrorist groups - Catholicism, Protestantism and Islam - actually condones the violent taking of life. Perhaps the question should be, can a terrorist really believe in God?
Sean Lang is honorary secretary of the Historical Association and teaches at Long Road Sixth Form College, Cambridge