No matter how far into Indian airspace Pakistan's naval surveillance aircraft had or had not penetrated, the concept of an unarmed, propeller-driven plane acting 'in a hostile manner' towards two MiG-21 jet fighters sent to intercept it is difficult to grasp. The 24-year-old plane's precise location at the time of the incident will probably never be established. But the response of the Indian Air Force that shot it down can more easily be assessed. Sixteen people have been killed because of reckless over-reaction to what may have been an intrusion of territory, possibly even a spy mission. But that cannot justify destroying an unarmed, low and slow aircraft, which offered no real threat and could probably have been chased away. Such extremes of behaviour can only put resolution of the Kashmir dispute further out of reach than it was at the end of last month's rebel incursion. It seems inconceivable that as recently as February the two prime ministers were meeting in Lahore to sign a memorandum of understanding, signifying a new determination to resolve disputes through negotiation. Since then, both sides have largely abandoned diplomacy; but it might have been expected after last month's border conflict in which about 1,200 lives were lost, that reason would prevail. The rashness with which these two nuclear nations pursue their mutual grievances is a matter of international concern. There can be no stability on the sub-continent, or in global terms until both sides recognise the need to stop hostilities and sit down to talk. India's insistence that it can solve its own problems is not borne out by this act. Perhaps if the UN knocked heads together, both sides might see sense.