Through dark, rubble-strewn streets, Muslims and Croats trudge back to their ruined homes, possessions in knapsacks and blankets on their backs. The central park is a graveyard. The bodies of more than a hundred Muslims, butchered by the Serbs and thrown into the municipal rubbish dump, are still being reburied there. It is a slow process. The bodies can be buried only when they have been identified. Many have been disfigured, not just by time but also by torture.
Mostar is the cutting edge of the new Croatia, a region brutalised by war - suspicious and frightening: frightening for its Muslim 'allies', as much as anyone. The ultimatum delivered on Sunday by Croatian leaders in Bosnia to the Bosnian government forces in Sarajevo is the latest example of how the well-armed Croats, with their headquarters in Mostar, are flexing their muscles, with what may prove to be disastrous consequences.
The Croats have come a long way in the 14 months since they declared independence from Yugoslavia. Then, the rhetoric was of democracy, the European Community, and the market economy. Today Croats are angry and suspicious that the West has failed to curb the aggressive territorial designs of the stronger and more numerous Serbs. In place of last year's faith in the new world order, older and uglier ideologies are on the rise.
In Herzeg-Bosnia, where war still rages, this radicalisation of Croatian opinion has gone furthest. In Zagreb last year, the slogan 'UN please come to Croatia' used to hang in the main square. In Mostar, by contrast, there are posters of Ante Pavelic, Croatia's war-time dictator in the Nazi- backed Ustashe regime.
Lorries roar through the villages of Herzeg-Bosnia with Ustashe slogans (the commonest is 'Za Dom Spremni', 'Ready for the homeland') emblazoned on the front. The militarisation of society is almost total. There is hardly a man under the age of 60 who is not in uniform, and many women also bear arms.
The Croats used to welcome the Western press. Now journalists are seen as a nuisance, or worse. In Mostar's press centre, where the new Herzeg-Bosnia radio and television stations are based, a young soldier drummed me out of the building, yelling and jabbing a rifle butt at my head. Other soldiers, manning the checkpoints in the city, were no less hostile. As they searched my car for the umpteenth time they grumbled about Serbian spies. Even in the cafes and restaurants in outlying villages, as a foreigner and obviously a journalist, I was shunned by the crowd of young Croatian soldiers sitting at nearby tables.
In Senj, a long way from Herzeg-Bosnia, on the Adriatic coast, local fishermen booed and whistled when Franjo Tudjman, the President of Croatia, came on the screen. The sight of the Croatian leader talking to a senior United Nations official met with derision. One sailor shouted 'Unprofor (the UN protection force) is Unproserb]', and the others laughed.
Croatia is still a country which feels very much at war. The police stopped my car more than 20 times as I drove across Croatia. In many towns in Slavonia, the proximity to the battle zones on the other side of the Sava river in Bosnia means black-outs are still observed. In Slavonski Brod, shells fired from Serb-controlled parts of Bosnia daily kill or wound several people. Croatia is full of policemen and soldiers.
The sullen mood in Croatia proper is linked to a widespread feeling of having been cheated by the UN peace plan. In Herzeg- Bosnia, the mood of hostility seems to spring from a determination not to be hoodwinked in the same way.
After eight months of the UN plan, not one Croatian refugee has been returned home to Serb- controlled regions of Croatia. Instead, even in the border 'pink zone', which the UN is supposed to hand back to Croat control, local Serbs demolish Catholic churches and drive out the Croats with impunity. There is evidence that this erosion of the region's Croat identity goes on under the noses of the UN monitors.
One example is the county of Benkovac. It was half Croat and half Serb before the war began. Secure behind their UN umbrella, the Serbs have since expelled all but a handful of Croats from their homes. The UN plan operates so exclusively in the interests of the local Serbs that moderate Croats who backed it have little to say for their efforts. Many Croats now equate trusting the West with appeasing the territorial appetite of the Serbian leader, Slobodan Milosevic. Herzeg-Bosnia is one of the first ugly fruits of the West's failure to act on its own stated principles in Yugoslavia - one of which was that borders must not be changed by force, and people must not be forced from their homes.
Its leaders, Bosnian Croats, are hard, ruthless men. They have seen what the Serbs got away with in Croatia and are determined to do likewise in Bosnia.
Their faith in gunpower and reverence for the memory of the Ustashe spring from the bitter experience of their relatives in Croatia itself.
In Muslim-controlled Zenica, a touching faith in the West still survives. The mayor said Muslims in Bosnia were not fundamentalists but true Europeans. He spoke of democracy, the EC, the evil of 'ethnic cleansing', the need to reassure Serbs in Zenica that they were still welcome. It seemed a long way from Mostar. But Croats have been at war for more than a year. Bosnian Muslims have been at war for less than six months. It will be a miracle if the spirit of Zenica survives.