The British government is today expected to announce plans for an expanded Nato mission in Afghanistan comprising 3,000 to 4,000 new troops.
British Secretary of Defence John Reid told parliament yesterday he had not made his final decision about the deployment but would make an announcement after consulting cabinet colleagues over the next 24 hours.
However, the Ministry of Defence confirmed that about 3,000 troops had been training in southern England this week "for a possible deployment to Afghanistan".
Mr Reid is to visit them tomorrow, the day after his announcement to parliament about deployment plans.
Britain has already committed itself to sending a contingent of about 900 troops to join about 1,000 it has in Afghanistan now, when it takes over command of the Nato peacekeeping force in Afghanistan in May.
A substantially larger Nato force is needed to take over the fighting duties now carried out by 18,000 US troops.
Some European countries have been reluctant to commit troops to a mission that will see a greater risk of combat, however.