The prime minister has told British soldiers in Iraq that they must "win the peace" as well as the war.

Making a surprise visit to the southern Iraqi city of Basra yesterday, Tony Blair said the war was in a "noble and good cause" but revealed that several thousand soldiers will remain in Iraq until at least 2006.

He told assembled troops that they are the "new pioneers of soldiering in the 21st century".

"I don't think the reputation of the British armed forces has ever been higher than it is today or its prestige any greater," he said.

Liberal Democrat leader Charles Kennedy said: "It is proper and fitting for the prime minister to pay personal tribute on behalf of us all to the skill and professionalism being shown by British forces in Iraq. They represent democracy in a country that was tyrannised.

"But after Lord Hutton's report, the democratic debate at home over the basis on which we went to war must, equally, be fully re-engaged."