He is Corporal Gordon Alexander Pritchard, of the Royal Scots Dragoon Guards, another casualty of war. His death yesterday was a grim milestone - the 100th British soldier to die in Iraq.

The 31-year-old, who was killed by a roadside bomb, had three children. He was a veteran of Bosnia and Kosovo. His brother Peter and father, Bill, were soldiers in the same regiment.

Last night, as his distraught wife, Julie-Anne, was being comforted by the family in Edinburgh, the death sparked protests once again over this most bitterly divisive of conflicts, with fresh demands for British troops to be pulled out of Iraq. A cross-party group of MPs renewed their calls for an inquiry into Tony Blair's conduct in taking Britain into the war.

Three other soldiers were injured, one seriously, when their Land Rover was blasted by an explosive device in the early hours of yesterday while on a routine supply-run, killing Cpl Pritchard, who was leading a convoy of three vehicles. The wounded were treated at Shaiba medical facility south of Basra.

Cpl Pritchard's parents, Bill and Jenny, said: "He was the epitome of a modern professional soldier. He was a well-trained, well-motivated soldier serving in a regiment that he was extremely proud of, as did his father and elder brother. He was a loving son and a very proud family man and he'll be very deeply missed by us all."

The men were ambushed near the Ten Platforms Port at Umm Qasr, south of Basra, which is held up by British authorities as an example of stability, with a deep-water harbour that is important for the future prosperity of "liberated" Iraq.

The former defence minister Peter Kilfoyle said the death of the 100th British soldier in Iraq was "testament to a war that should never have been embarked upon".

He urged Mr Blair to make it clear in Prime Minister's Questions today that Britain's military presence in Iraq is not open-ended. "There should be a clear statement of intent that the deployment of troops is indeterminate," he said.

The recriminations came as the Prime Minister was hosting an emergency international summit on Afghanistan, a country left on the brink of disintegration after another US and British invasion, before the "war on terror" moved to Iraq.

Mr Blair, John Reid, the Defence Secretary, and other government ministers expressed their condolences over the deaths of Cpl Pritchard and others killed in the conflict. But they made it clear that the deaths would not lead to a withdrawal from Iraq or stop the deployment of almost 6,000 British troops to Afghanistan.

Opening the summit on Afghanistan Mr Blair said: "The British troops who go to Afghanistan face dangers there, as they do in Iraq. We are determined to see this through. This is a struggle for freedom and moderation and for democracy. It's a tragedy when we lose any soldier. But we have to understand why it's important that we see this through. It is important because what is happening in Afghanistan and Iraq is that the people of those countries want to leave behind terrorism and extremism and they want to embrace democracy."

Mr Reid said the death of Cpl Pritchard was cause for reflection on the role Britain's armed forces had played in "lifting the burden of tyranny" and bringing stability.

Reg Keys, whose son was one of six Royal Military Policemen killed at Majr al-Kabir, in Maysan province, and who stood against the Prime Minister in the general election, said: "We have had 100 chances to learn our lesson. It just goes on and on. The lads are dying for a falsehood. As long as we are there, we will see a steady trickle of coffins coming back home. The military and political leaders should hang their heads in shame."

Anti-war demonstrators, including six MPs, read out the names of the British dead in Iraq and placed a hundred wooden crosses in their memory at Parliament Square. A similar act recently led to the arrests of a young man and a woman, but this time the police did not intervene.

Deaths in Iraq

COALITION MILITARY DEAD:

US 2,245

UK 100

Italy 27

Ukraine 18

Poland 17

Bulgaria 13

Spain 11

Slovakia 3

El Salvador 2

Estonia 2

Netherlands 2

Thailand 2

Denmark 2

Hungary 1

Kazakhstan 1

Australia 1

Latvia 1

IRAQI DEATHS:

Iraqi military, security and police deaths since official end of the war in June 2003 4,059

Iraqi civilians since end of war: 28,287 - 31,891

OTHERS:

Contractors (various nationalities): 353

Journalists: 79 dead (2 missing)

Sources: Iraq body count, The Brookings Institute, www.icasualties.org, Reporters Without Borders, Project on Defense Alternatives