Early wins in a major anti-Taliban push in southern Afghanistan offered a "beacon of hope", British Prime Minister Gordon Brown said yesterday during a surprise visit to troops.

During a lightning eight-hour visit to Helmand province, Brown cautioned that it was vital to "win the peace as well as the war" and vowed that British troops would stay in Afghanistan until their job was done.

"That's why it's so crucial that in just 20 days since the start of the operation, the combined international and Afghan forces, military and civilian, have begun turning a stronghold of brutal Taliban insurgency into a beacon of hope for local people," he told reporters.

Before Brown left Camp Bastion, one of the biggest military bases in Afghanistan, Britain's Ministry of Defence reported the death of a British soldier in an explosion in Helmand last Friday.

The death in the Sangin district, which the ministry said was not connected to the ongoing assault that Brown referred to, brings to 269 the number of British troops killed since operations in Afghanistan began in October 2001.

In what is likely to be his last trip to Afghanistan before a general election expected on May 6, Brown met British troops at Camp Bastion and two frontline posts in Nad Ali, including one taken in Operation Mushtarak, currently under way in Helmand.

Mushtarak, in which US Marines have led 15,000 troops against Taliban insurgents in two poppy growing districts, Marjah and Nad Ali, is the first test of a counter-insurgency strategy for speeding an end to the war.

Around 4,000 of Britain's 10,000 troops in Afghanistan have been taking part in the campaign launched on February 13, in which troops are now consolidating control of the opium-producing target area.

Commanders on the ground have said they do not yet have complete control, but are paving the way for Afghan-led security and civil services.

Recent gains in Operation Mushtarak are set to be followed up in other Taliban strongholds in Helmand and neighbouring Kandahar province over the coming 12-18 months.

But the International Committee of the Red Cross (ICRC), in a strong statement issued in Kabul, warned that civilian control in the the Marjah area was still elusive due to the Taliban's lingering presence in the area.