Muslim-Croat war interrupts aid supplies: While central Bosnia is still engulfed in fighting, British troops try to keep the convoys moving

'WE'RE in a war but we're not at war.' Lieutenant-Colonel Alastair Duncan's phrase sums up the dilemma of the British troops in central Bosnia, who are constantly in the midst of gunfire but seldom the target - except when local forces make a mistake.

While attention is focused on Sarajevo, squeezed and surrounded by the Serbs, fighting continues between Muslims and Croats in central Bosnia. But aid passes up the UN aid route past the British bases at Gornji Vakuf and Vitez, which Col Duncan commands, and up to warehouses in the Muslim stronghold of Zenica. Interruptions are due to fighting between the predominantly Muslim Bosnian national army (BiH) and the Bosnian Croat HVO - not the Bosnian Serb Army (BSA). The British commander at Gornji Vakuf, Major Graham Binns, has continued to negotiate 'windows' through which the aid can pass.

On Wednesday fierce fighting broke out again around the British UN base at Gornji Vakuf. The BiH had established control over the mixed Croat and Muslim town, but on Wednesday the Croats launched their counter-attack.

On Wednesday the Croats positioned a T-55 tank on the high ground south of Gornji Vakuf, but what followed illustrates how poorly trained and amateurish these forces are. They fired about 100 rounds - 100mm tank shells - in about two hours, but did not move the tank once. The BiH, far less lavishly equipped, were therefore able to locate and destroy it.

On 1 August a Royal Engineers team were filling in holes in the road near the 'T-junction' west of Vitez when BiH troops to the west opened fire. It seems they saw troops digging and thought they were HVO. When a nearby British Warrior infantry fighting vehicle returned fire they realised their error and stopped. The latest BiH offensive began at dawn on 31 July with attacks along the line Bistrica-Krupa-Gornji Vakuf and Prozor, supported by heavy artillery and mortars. It appeared a well planned and executed offensive, but it cut across the main UN supply route 'Diamond'.

Just before 6pm, 29 artillery or mortar rounds landed in Gornji Vakuf. The BiH captured most of the town. On 2 August the BiH attacked the HVO headquarters in the town, which is next to the British base. Here, separated from Vitez by a rocky canyon once infested with bandits, 220 troops are based - B Company of the Prince of Wales's Own Regiment of Yorkshire, Royal Engineers and medical support. Rounds landed within 150m of the British perimeter.

On Wednesday, the HVO hit back. At first, UN observers thought they were trying to establish a defensive position between the HVO's Makljen checkpoint, on top of a spectacular rocky ridge on the main road north of Prozor, and Gornji Vakuf, but it soon became apparent that it was a counter-attack.

The Muslims and Croats are showing increased ingenuity in making their own weapons. One expedient is to fill fire extinguishers with high explosive and fire them from home-made mortars about 300m. In trench warfare, such improvisations can be very effective.

Captain Peter Bullock, with the British force in Vitez, said 'some of the equipment we're seeing round here is the sort of technology we'd associate with the Provisional IRA - heavy welded mild steel - that sort of thing.'

Vitez itself - a Croat enclave surrounded by Muslim brigades - has been very quiet. Two weeks ago, everybody expected a Muslim assault down the Lasva valley from the west. Before I left, our landlady explained her plans to douse the house in petrol and set it on fire if the Muslims came in.

But the Croats still hold their positions, including the Princip explosives factory south of Vitez. It is named after the Serb nationalist student Gavrilo Princip, whose assassination of Archduke Franz Ferdinand precipitated the First World War. The Muslims hold positions south of it. The Croats have said it will never fall into Muslim hands, leading to speculation that they might blow it up.

(Photograph and map omitted)