When the full force is in place, it will be a third larger than originally planned - 2,400 troops instead of 1,800. The target date for beginning escort duties - protecting UN convoys - is 13 November. The troops now being deployed will be in Bosnia for six months, after which the Ministry of Defence plans to replace them with new units.
But although the number of troops - and senior officers - is being increased, the force is not taking extra combat equipment such as helicopters or radars to locate mortars or artillery, in spite of the difficulties encountered by a reconnaissance party, which returned on 1 October. Of the extra 600 British troops, 200 will form part of the multinational headquarters and 400 are engineers, who will set up facilities. They will be withdrawn after about three months.
The British force is centred on an armoured infantry battalion of the Cheshire Regiment, reinforced by men from the 2nd Battalion Royal Irish regiment. But it has a logistic 'tail' closer to a brigade.
The British in Bosnia will be commanded by a Brigadier, Andrew Cumming, who will initially be based, on board the logistic landing ship Sir Bedivere off the Croatian port of Split.
The British battalion group will be one of four battalions, along with others from France, Canada and Spain, in a new Bosnian command. This will be called Unprofor II. It will be commanded by a French officer, Major General Philippe Morillon.
Malcolm Rifkind, the Secretary of State for Defence, said in London that the advance party of 90 troops would fly to Split during the next three days.
Asked about the criticism of Cyrus Vance, the UN special envoy, of the time it has taken for the British to get operational, Mr Rifkind said: 'Of course I share Cy Vance's concern. It's very important that these men should get there as quickly as possible. Some extra time is required because of the change of route.'
Brigadier David Jenkins, the MoD's Director of Military Operations, said the initial plan had been to take food to depots across northern Bosnia from the east - from Loznica in Serbia. 'We discovered that it was difficult to run aid across ethnic boundaries. Much better to run with the ethnic grain. We tried to get to Jajce and we couldn't because there's a lot of fighting.'
By the end of the month, Mr Rifkind said, a party of 1,000 troops will have reached Split, where they will meet vehicles and equipment brought by Sir Bedivere and a chartered vessel. Sir Bedivere is due to dock on 27 October.
Brigadier Jenkins said that the Army had considered sending helicopters but that 'at present their survival rate is not high. People have a nasty habit of firing at them'. On the lack of mortar-locating radars, he said: 'If you start engaging in a fire-fight with the local people you're not carrying out the UN mandate.'