London:
Tony Blair, the former prime minister, appeared on Friday before a British inquiry into the origins and conduct of the Iraq war to fill in gaps from earlier testimony about his unpublicized discussions with President George W. Bush as the conflict loomed.
It was his second appearance in a year, reflecting the inquiry's desire to "clarify what happened" when Mr. Blair led the country into a deeply unpopular war, the panel's chairman, Sir John Chilcot, said.
The last time he appeared before the inquiry, in January, 2010 , he was questioned for six hours and mounted a fluent and unwavering defense of his actions, saying he would do the same again to counter what he depicted as a threat from Saddam Hussein that had assumed far greater dimensions after the attacks of Sept. 11, 2001.
On Friday, he again invoked the Sept. 11 attacks as the source of his subsequent policies towards Iraq, terrorism and unconventional weapons.
Tanned and wearing a navy blue suit, Mr. Blair said the attacks on the World Trade Center in New York and the Pentagon in Washington created a new type of terrorism.
"The single most difficult thing we have to face today -- and we face it still -- is the risk of this new type of terrorism and extremism based on an ideological perversion of the faith of Islam combined with technology that allows them to kill people on a large scale," Mr. Blair said
"Although this is a time where many people think this extremism can be managed, I personally don't think that is true. I think it has to be confronted and changed."
Previous witnesses at the inquiry, which opened in July 2009, have insisted that British security services concluded that there was no evidence of links between Saddam Hussein and Al Qaeda and the possibility of terrorists obtaining unconventional weapons.
Last July, Dame Eliza Manningham-Buller, a former head of MI5, said the domestic intelligence service had had no concerns "in either the short term or medium term" to support Mr. Blair's frequent contention that he acted to prevent terrorists securing access to unconventional weapons in Iraq.
Mr. Blair said on Friday that after Sept. 11, two views emerged internationally concerning terrorism, one of them that the threat could simply be managed. His own view, he said, was "that we have to confront it."
After the attacks, he said, "We always did make it clear that we were going to be shoulder to shoulder with the Americans."
He dwelt at some length on the domestic British politics which, he said, underpinned the concerns of some of his cabinet colleagues about an alliance with the United States.
"Here we were. We had just been re-elected with another landslide, we were probably the most successful center-left government in the world and you are about to go into an alliance with a conservative, Republican president. That was the thing that worried them most," Mr. Blair said.
But he acknowledged that, while British policy did not speak specifically of regime change, the notion of ousting Saddam Hussein had long been an American priority and he had discussed it with President Bush in a telephone conversation in December 2001.
"Regime change was their policy so regime change was part of the discussion," he said. "If it became the only way of dealing with this issue, we were going to be up for that."
For the Bush administration, "from Sept. 11 onwards, this was on their agenda," he said.
Although almost eight years have gone by since Mr. Blair committed British troops as the junior partner in the United States-led invasion of 2003, the war has become intertwined with Mr. Blair's memory and legacy for many Britons.
Britain's involvement in the conflict was deeply unpopular, stripping Mr. Blair of the immense backing that brought him to office in 1997 before his resignation a decade later.
While the British authorities have refused to make public key documents about the transatlantic relationship at that time, many Britons remain concerned about both the legal justification for the war and the extent of Mr. Blair's pledges to Mr. Bush as the preparations for the invasion got under way.
Sir John, the chairman of the panel, has voiced disappointment at a decision by a senior civil servant, Sir Gus O'Donnell, to keep notes of those exchanges secret.
In recent days, the former attorney general, Lord Peter Goldsmith, whose job was to scrutinize the legal basis for the effort to topple Saddam Hussein, has said that he was "uncomfortable" with some of Mr. Blair's remarks at the time suggesting that the invasion had sufficient United Nations support to justify war.
Mr. Blair also faces scrutiny at a more personal level. Reg Keys, whose son was killed in southern Iraq in June, 2003, said this week he planned to be present when the former prime minister testifies. His son, Tom Keys, was among six British military police officers killed by an Iraqi crowd.
"Had he been killed by weapons of mass destruction -- had Iraq possessed them -- I would accept that," Mr. Keys said. "But I will not accept that a prime minister in the 21st century can mislead Parliament and get away with it."
Since late Thursday, anti-war demonstrators have been gathering outside the Queen Elizabeth II conference center here to protest Mr. Blair's actions in Iraq.