If only what? Whenever there is a tragedy of this sort individuals and interest groups leap into the limelight with the wisdom of hindsight to say that if their warnings had been heeded, the tragedy could have been averted. Sometimes they are right, as when they point to the shockingly inadequate regulation of adventure holidays and the lack of seat belts and other safety measures for school buses - a point driven home yesterday by another fatal bus accident.
But the attack at Hall Garth school seems to fall into a different category. To make all schools secure against all intruders would cost large sums of money that are badly needed for other purposes. Even if it were possible, it would not avert the more common threat of violence from pupils and parents with legitimate reasons for entering school premises.
Some things can, of course, be done to reduce dangers from intruders, many of which have been tried on a patchy basis. More vigilance and better alarm systems would help, as would basic training for teachers and pupils in how to respond to muggers, terrorists, hostage-takers and the mentally disturbed. Such techniques are sadly becoming part of everyone's survival equipment in today's world, so the effort would have wider value. More useful still, and more effective than fences around schools, would be better care for the mentally ill. Over the past five years, 41 murders in England have been attributed to schizophrenics.
But it needs to be accepted, without succumbing to complacency, that not all accidents are preventable nor all tragedies avoidable. Buying safety, whether in schools, on the roads, in the air or on adventure holidays, is always a matter of balancing costs against risks. Absolute safety is unattainable in any sphere; death is everyone's constant companion.
All we can do is seek the reasonable reduction of risk. Then, when accidents occur, we should bring more rigour to the task of distinguishing between those that require allocations of blame or spasms of corrective action and those which call mainly for sympathy and mourning.