Last year the bombs were the first shock. The second was to discover that the terrorists were suicide bombers and British. We could have coped with the outrage more easily had the murderers been foreigners, raised in squalor, brainwashed under a theocratic dictatorship and shipped here to massacre people for whom they had no kindred feelings.

It is more plausible that we could defend the country against an exterior threat than defeat one that comes from within. We can hope to monitor comings and goings at our airports and to keep tabs on people who stand out because they are visitors. But the task is almost hopeless if the perpetrators live among us. If four young men who had enjoyed the advantages of life in Britain decide to kill themselves and as many others as possible, then why should there not be 400 or 4,000 more?

Once we understand that, we feel less safe. Also, things have got worse over the past year. Although there has been no anti-Islamic backlash it seems that many British Muslims feel victimised by the authorities’ response to terror. They think they face discrimination when stopped and searched. The bungled police operation in Forest Gate has become an emblem of supposed repression.

Even peace-loving Muslim spokesmen feel obliged to give credence to the perception that their community is being unfairly harassed. It causes some young Muslim men to withdraw further from a British society claimed to be hostile. At best that surrounds the terrorists with a penumbra of disaffected Muslims who may not condemn their crimes or denounce their murderous plots. At worst it enlarges the pool from which new bombers can be recruited.

It is there that Al-Qaeda has scored its greatest success. More significant for the long term than the bombs is the impact that terror has in dividing the groups that make up our society, and in increasing the appeal of militancy to those who can be duped into seeing themselves as repressed.

Muslim complaints about being victimised are perversely directed. Muslims are victims of the bombers, not of the state or the police. It is the terrorists who make Muslims potential objects of suspicion and fear because the bombers murder in the name of Islam. Muslims have every right to be outraged, but their fury should focus on the men of violence. The police action in Forest Gate was cack-handed and the shooting of one of the “suspects” was indefensible. But given the profile of the terrorists, Muslims are bound to be more affected. By analogy, when police are looking for a rapist they interview males without anyone believing them to be institutional men haters.

There are those who in the interests of community relations denounce linking the word Islamic to “violence” or “extremism”. They object that we did not call the IRA “Catholic terrorists”, nor do we speak of “Christian extremism” or link Christian fundamentalism to violence.

There are good reasons for that. Although the IRA is rooted in the Catholic community, its aims are political and secular. Although there certainly are Christian extremists today, just now they are not murdering people in the name of purifying the world. By contrast, across the globe human beings are being slaughtered in large numbers by Muslims quoting from the Koran and vowing death to infidels, including other Muslim sects. Their objectives are political and religious.

So to try to condemn the expression “Islamic violence” is a dangerous attempt at censorship that would hamper our understanding of the threat we face. The term is certainly offensive to Muslims, but the offence is caused by the bombers, not by those who describe the process.

Last week Tony Blair caused a furore by calling on Muslims to do more to control, denounce or deliver up the men who preach and practise violence. Some Muslim spokesmen said that was a divisive remark that stigmatised Muslims instead of recognising that the problem was one for British society as a whole.

The prime minister’s exhortation was valid. The bombers are not casualties of British society. Shehzad Tanweer, the Aldgate murderer, was only 22 yet left £121,000 after tax. The bombers’ grievances cannot be bought off with more money for schools or a new youth centre. They were corrupted, I assume, by theoreticians of annihilation from within their community. Their training was probably perfected in an Al-Qaeda camp in Pakistan.

Abdur-Raheem Green is an imam who believes that he preached to some of the 7/7 murderers and hopes that nothing he said encouraged them. When asked last week whether he would turn over to the authorities young men who were moving towards terrorism, his answer was ambiguous. He argued that it would be better for him to dissuade them rather than denounce them because that would risk creating further alienation. That is not the response that Blair, speaking for most Britons, is seeking.

Times Recommends

• Chelsea Flower Show has lost the plot
• The age of personal vitriolic abuse
• Obama: the new Great Redeemer