During that visit I travelled out with the British verifiers, mostly former soldiers, as they looked at the evidence of almost daily violent deaths on both sides, and as they put themselves at risk in trying to damp down tensions on the ground. Even as we stood in their small operations room discussing the photographs of the latest slaughter, word was coming in of yet another episode in the Kosovo tragedy, with an even higher death toll. A few minutes later more news came in, this time of an attack on Serb teenagers in a bar by the Kosovo Liberation Army, which seemed to mark the beginning of a new "dirty war", targeting civilians as well as Serb security personnel.
The October agreement brokered by Richard Holbrooke had completely run out of steam well before Christmas, the unarmed verifiers were having their authority eroded daily, and the time that the deal bought for us to find a political solution in Kosovo has been wasted - not least by delays in getting the verifiers out into the field, and because of the Albanian community's inability to speak with one voice. That agreement, for all its faults, created a political dynamic strong enough to replace the dynamic of force for a time and, crucially, it opened up the opportunity for the international community to become involved. And that involvement, in the form of OSCE (Organisation for Security and Co-operation in Europe) verifiers, has made a measurable difference in certain specific situations on the ground, but has proved inadequate when violence and reprisals begin to escalate again. It is certainly no substitute for a political solution.
The extraction force over the border in Macedonia is a useful political symbol but would be of no real military use as a force to pull out the verifiers, and so the monitors are still all we have. But with violence escalating again, they are clearly an inadequate barrier between the warring sides; they are unprotected and their authority has been undermined by Belgrade and by the Serb and the KLA commanders in the field.
Now we can see the province sliding back into war. It has been swift but not unexpected, particularly not to those of us who had been arguing for earlier intervention since the middle of last year. Casualties have been mounting on both sides, and this week's atrocity in Racak represents a fundamental challenge to the West's policy.
We have one last chance to persuade both sides but, most urgently, President Milosevic, to accept the authority of the international community and return to compliance with the terms of the ceasefire - including full co-operation with the International War Crimes Tribunal investigators as specified in UN Resolution 1199, which governs the ceasefire.
But if these last-ditch efforts fail - and I am pessimistic - we must consider our options, which have been narrowing with every month that passes. If we do fail, then Nato and the OSCE will be faced with a very stark choice: to take the verifiers out, or to send the troops in.
Neither decision will be easy. On the face of it, the obvious decision would be to pull the verifiers out. But I do not believe that we in the West could allow ourselves to stand aside and be spectators in the carnage that would ensue. I have no doubt that Milosevic and the increasingly powerful right-wing nationalists who dominate politics in Belgrade would see withdrawal of the verifiers as a signal of a failure of the international community's will, a green light for a full-scale campaign against the Albanian population in Kosovo.
The region would be flooded with the main battle units of the Yugoslav army - the fifth most powerful army in Europe - and we would see the Serbs attempt a "final solution" to their Kosovo question. The bloodshed would be horrific, both for the Kosovar Albanians and for the minority Kosovar Serbs, and would almost inevitably ignite the wider Balkan conflict in Macedonia, Albania and the southern Balkans that we have all feared since the beginning of last year.
It is clearly inconceivable that we should stand back and allow this to happen. Air strikes may be used to prevent further instances of the use of excessive force and heavy weapons against defenceless Albanian villages, and to force Milosevic to return to compliance if Serbia uses heavy weapons against Albanian civilians in contravention of the Geneva Convention. But on their own, air strikes offer us only a way of dealing with Milosevic's aggression, not a way of dealing with the KLA or with the steady trickle of weapons and ill-trained young men and women who attack from across the Albanian border - attacks probably sponsored by money from the Albanian diaspora and which frequently send the young volunteers to their deaths. So now we must think the unthinkable, and consider the least worst option of putting troops in on the ground.
This is profoundly undesirable, it is no small step, and has long-term implications. It puts into question the status of Kosovo as a province of Serbia and it would mean an occupation of the sovereign territory of the Serbian state by Nato forces. It would be a real challenge to Europe's as yet unproven ability to handle a co-ordinated peace-keeping mission. But the actions of the Serbs in perpetrating the atrocities in Racak and elsewhere, and in flouting the decisions of the international community, have diminished or removed their moral authority to govern Kosovo on the basis of 5 per cent of Kosovo's population.
The present policy has one last chance - and if it works we must urgently reinvest the political process with the momentum it needs - but if it fails we must be prepared for the worst and for the only option we have left. We have, once again, as in Bosnia, done too little too late, and we have left ourselves no good options and no other choice.
I asked one of the verifiers whom I met whether he could detect a will for peace in Kosovo. He replied: "I can't see a will for peace. But I can see a will not to return to war." That may be all we have to go on in our hopes to build a future for the region, but we cannot and must not stand aside.