Cook reads the riot act to Bosnia's divided leaders

Britain is cracking the whip over the recalcitrant parties in Bosnia, amid Western fears that continuing failure to implement the Dayton peace accords will make a mockery of Nato's plans to wind up its peace-keeping mission by the middle of next year

Now on the second day of a two-day trip taking in Sarajevo, Banja Luka and Zagreb, Robin Cook, the Foreign Secretary, is using an array of diplomatic carrots and sticks - from the prospect of greater aid from Europe, to threats of further action to seize alleged war criminals.

The backdrop is grim. More than 18 months after Dayton, the bulk of the accords' provisions are unmet. Reintegration of previously warring communities has been fitful. From phone systems and property laws to flags and the symbols of state, ethnic divisions prevail. On a host of issues, including corruption and media freedom, Mr Cook has said he expects "frank exchanges" with Muslim, Serb and Croat leaders.

With its swoop this month against two alleged Bosnian Serb war criminals, one of whom was shot dead by SAS forces, Britain has shown it means business. "We've shown we're ready to act as well as talk," warned a senior official accompanying Mr Cook.

"But this will be a grindingly slow process." No obstacle is bigger than the stance of the Bosnian Serbs, divided between President Biljana Plavsic and her predecessor, Radovan Karadzic, top of the war criminal wanted list but still a malign force from his stronghold of Pale.

Ensconced in Banja Luka, Ms Plavsic is seen as wanting to rebuild ties with the West. As the British official put it: "Ms Plavsic is no angel. But she understands that it is in the interest of the Republika Srpska that Dayton is implemented."

Such comparative reasonableness may earn Bosnia assistance from the European Union, targeted at the Banja Luka region.