Leading article: We can stop young killers

Every now and then the power of the human spirit to contradict expectations makes a lasting impression on a whole society. Ten days ago, Jimmy Mizen was just another teenager who had been murdered in London. The 13th this year. The details barely registered. Nice guy. Not in a gang. Tried to avoid a piece of low-level thuggery in a baker's shop, which resulted in a broken window. Stabbed with a piece of glass. Ghastly business. Something must be done. What did Boris say he would do about feral, violent youths? Didn't Jacqui Smith say something about harassing them? Next story.

Except that, this time, we did not move on to the next story quite so easily. Because there were Jimmy's parents yesterday. Like the man with the carrier bags standing in front of the tank in Tiananmen Square, they would not let the public caravan roll on. "Anger breeds anger, and bitterness will destroy my family if I'm not careful – and I won't allow that to happen," Margaret Mizen said.

Of course, many bereaved parents respond to the death of a child with dignity, grace and forgiveness, even if most of us find it impossible to imagine that we could behave with such forbearance in their place. But to bear public witness to such a message of hope is extraordinary.

Hence the impact of the words of Barry, Jimmy's father: "It does not have to be like this. People are saying something must be done. I just wonder how futile it is with more and more legislation and laws. Perhaps we all need to look to ourselves and look to the values we would like and our responses to situations in our life. Sometimes we might be drawn into certain ways of our living. It is our choice but change has got to come from all of us."

There comes a time in the history of many a terrible, apparently insoluble problem when a voice cuts through the fatalism to make change seem possible. Thus, out of the despair of the Remembrance Day bomb in Enniskillen in 1987, came the voice of Gordon Wilson, whose daughter Marie had died. In an interview with the BBC, he said: "I bear no ill will. I bear no grudge. Dirty sort of talk is not going to bring her back to life." Although the IRA's murder campaign continued fitfully for another decade, Enniskillen was a turning point, and Mr Wilson's response played a significant role in undercutting popular support among Roman Catholics for terrorism.

Nor was Mr Wilson alone. The work done by Colin Parry, whose son Tim was killed in the Warrington bomb of 1993, had a similar effect in clarifying public attitudes – on both sides of the Irish Sea. Looking back, the mainland bombing campaign was an admission of weakness by the republican proponents of the armed struggle, but Mr Parry's Foundation for Peace and his willingness to meet Gerry Adams helped further to isolate them.

Plainly, Irish republicanism and teenage thuggery are rather different phenomena. But there are analogies. For a long time, IRA violence was simply regarded as one of those things. The main response was to try to contain it and to live with it. Similarly, there has been a tendency to regard youth stabbings as the visible tip of an iceberg of anti-social and criminal behaviour that was mostly contained within gangs of young black men. Certainly, we believe that we are justified in resisting the portrayal of teenagers generally as knife-wielding crazies. But the recent statistics on murders of teenagers by teenagers are alarming, and it takes something out of the ordinary, such as Margaret and Barry Mizen's response to their son's murder, to make us see such things clearly.

It is no use, as Barry Mizen says, simply demanding more laws. Nor is it a matter of heavier policing or of – the most feeble of excuses – "giving young people something to do" (as if lack of facilities for ping pong leads 13-year-olds to knife each other). As Mr and Mrs Mizen say, more plausible answers lie in looking to ourselves, promoting a culture of personal responsibility. Of course, this is difficult territory. Attempts to propose remedies disappear too often into a well-meaning rhetorical mush. Many politicians have ventured into this urban jungle. David Cameron has made the point that governments cannot substitute for individual morality. Gordon Brown spoke eloquently of the shared moral sense that is "the timeless wisdom of all the great religions" in his address to Church of Scotland General Assembly yesterday. Indeed, this Labour Government has done much to improve schools and job opportunities that make it easier for self-respect to flourish.

Yet we still face a serious and growing problem of lethal violence among young people. Just because there are no easy answers does not mean we have to accept it. Barry and Margaret Mizen have given us the chance to see that clearly. That is the best possible memorial for their son.