LEADER:The siren call of Little England

As we approach today's Commons debate on Bosnia, the air is full of the slithering sounds of worms on the turn. Many of the gung-ho merchants of two years ago - the apostles of "surgical strikes", the "sanctions are for wimps" sneerers and the "remember appeasement" school of historical over-simplification - are metamorphosing into a new "troops out" movement.

Suddenly, it is not Munich that offers a history lesson, but Vietnam. "Our soldiers did not join up to die for a country which has nothing to do with us," says Teresa Gorman. Really? So why were Teresa and pals so (rightly) keen on risking lives for Kuwait, or for a sparsely populated island in the South Atlantic? "There is only one thing worth fighting for in Bosnia," bellows the Sun, "and that is the lives of British troops." Even the more measured Daily Telegraph recognises that pulling out might lead to terrible suffering, but nevertheless concludes that "it is time to go".

The desertion of his right wing in the face of the enemy is bad news for Mr Major - especially since they articulate a widespread frustration with the failure of the international community to cope with the former Yugoslavia, and a real fear for the safety of British soldiers. Pictures of captive Britons in Visegrad evoke South Georgia and Port Stanley in April 1982, without the slightest chance of gaining suitable revenge.

The Prime Minister must not give in. The arguments for withdrawal are seductive, but those for staying put still have greater force. Yes, the lack of agreed strategy between the US, Russia, Europe and the UN has badly compromised the work for peace in the region. Yes, there is very little sign that diplomacy will work and that the war will come to an end. Yes, there is only the prospect of prolonged conflict, with our troops caught in the middle.

But the other side of the argument is more powerful. For three years now, British and other troops have done something of enormous moral and practical value. They have helped hundreds of thousands of ordinary Bosnians to survive the war. They have fed the starving, housed the homeless and brought medicine to those who would have died. For a large part of the population of this embattled state, Britain is a country that has tried to help, whatever the Bosnian government might say. Withdrawal would mean cutting off the aid, the probable fall of the enclaves and the partition of Sarajevo, provoking a massive exodus and leaving hundreds of thousands defenceless against the ethnic cleansers. Could we really live with that on our consciences?

The very fact that French, British, Dutch and other troops are still on the ground means we have not surrendered our interest in the region. If we did, that would leave the Russians as the power-brokers in Yugoslavia. UN troops on the ground have also been important in containing a possible spread of the conflict to neighbouring countries and regions. We may know what we have failed to achieve by our presence - but do we really understand what we have managed to avoid?

We have got to get this into our heads: Bosnia is the long haul. It could be a generation until - as in Northern Ireland or Lebanon - the sides sicken of pointless aggression. To persevere in a messy and often terrible world, at risk to yourself, takes courage and patience. So far we have shown those qualities - we should not now give in to moral cowardice or cheap demagoguery.