Ruling out withdrawal, he told the Labour Party's annual conference on Tuesday that "eight and a half million Iraqis showed which future they wanted when they came out and voted in January's elections".
Disquiet about Britain's involvement in Iraq has grown since 19 September, when rioters in the southern city of Basra attacked British troops with petrol bombs when the troops attempted to rescue two comrades who had been detained by Iraqi police.
"I know there are people, good people, who disagreed with the decision to remove Saddam by force," Blair said.
"Yes, several hundred people stoned British troops in Basra. Yes, several thousand run the terrorist insurgency around Baghdad. And yes, as a result of the fighting, innocent people tragically died."
Blair continued: "But eight and a half million Iraqis showed which future they wanted when they came out and voted in January's elections. And the way to stop the innocent dying is not to retreat, to withdraw, to hand these people over to the mercy of religious fanatics or relics of Saddam, but to stand up for their right to decide their government in the same democratic way the British people do."
"[Terrorism] is a global struggle. Today it is at its fiercest in Iraq. It has allied itself there with every reactionary element in the Middle East"
British Prime Minister Tony Blair
Blair also defended his partnership with US President George Bush.
"Britain should remain the strongest ally of the United States," he said.
"I never doubted after September 11 that our place was alongside America and I don't doubt it now. And for a very simple reason: Terrorism struck most dramatically in New York but it was aimed then and is aimed now, at us all, at our way of life.
"This is a global struggle. Today it is at its fiercest in Iraq. It has allied itself there with every reactionary element in the Middle East. Their aim: To wreck this December's first ever direct election for the government of Iraq."
No Iran attack
Meanwhile British cabinet ministers made it clear to the prime minister that they would not support any US military action against Iran, the Independent newspaper reported on Tuesday.
"I don't think there will be any attack on Iran. Certainly we would not be party to any such attack like that," Northern Ireland Secretary Peter Hain was quoted as saying in a fringe meeting at Labour's annual conference in Brighton, southern England.
UK ministers have told Blair they
will not support an attack on Iran
Last week, British Foreign Secretary Jack Straw insisted that the dispute over Iran's nuclear programme could only be resolved diplomatically.
"This will not be resolved by military means, let's be clear about that," he said.
Defence Secretary John Reid also told Sky News on Sunday that military action against Iran was not being discussed as a solution.
"Nobody in the British government or anybody I speak to is talking about that," Reid said. "No one is discussing military action against Iran", he emphasised.