In an exclusive interview with "This Week's" Christiane Amanpour, former UK prime minister Tony Blair said it was difficult for him to convince the Queen of England to acknowledge the wave of loss and anger following Princess Diana's sudden death in 1997, the year Blair became prime minister.
"Partly because of the loss, but partly because of the circumstances in -- in which she died, there was also a sense of anger. Now, some of that anger was directed at the paparazzi, but some of it, I think, was -- was directed at the establishment that people felt had let her down in some way," Blair told Amanpour.
"In the end, the queen did that (honored Diana), I think, magnificently," but he added that the task to talk to her was difficult. "It was difficult for me because I was a new prime minister and I didn't really know the queen. And, you know, it was -- I was very nervous in and around her, as you would be."
In his new autobiography, "A Journey: My Political Life," Blair defines Diana as a person who "captured the essence of an era and held it in her hand. ... She was extraordinarily captivating," he wrote.
Watch Christiane Amanpour's interview with Tony Blair tonight on "World News," and Wednesday on "Good Morning America."
Although the cause of Diana's death was blamed on her driver's recklessness, several paparazzi who were chasing the car in Paris were arrested.
"She'd almost become such public property -- I mean if you read the accounts of press pursuing her and paparazzi and so on, you know, I get a certain amount, or a political leader gets a certain amount, a film star gets a certain amount," Blair said. "I don't think we had any idea what it was like for her. It was just a constant pursuit."
Blair also defends former President Bill Clinton, who he dubs his political soul mate in the book.
"I think he was one of the first people really to understand, to articulate how progressive politics couldn't be a rainbow collation, that you had to stand up and be connected with people, not activists, simply," Blair told Amanpour.
The three-term prime minister praised Clinton "as one of the smartest politicians I've come across," and expressed confidence in Secretary of State Hillary Clinton leading the Middle East peace negotiations.
Clinton's two-term presidency was almost derailed because of his affair with Monica Lewinsky, an indiscretion that Blair wrote, "arose in part from his inordinate interest in and curiosity about people."
"Part of his genius [as] a politician is he is extraordinarily curious about people," Blair said today.
Blair also praised Hillary Clinton's negotiating skills, saying he is certain the secretary of state can confront all the challenges she is facing when it comes to international diplomacy.
"There is a lot on her shoulders. But she's completely capable of doing it," he said. "She's got the best type of political mind that knows where you meet the point of principle and knows where you need the subtlety and the compromise."
Blair is scheduled to receive the 2010 Liberty Medal from former President Clinton in Philadelphia on Sept. 13.
Blair: No Apologies for Iraq Attack
Blair took over the Labor Party's leadership in 1994 and spent three terms as prime minister, from May 1997 to June 2007.
He took considerable heat for supporting the 2003 U.S.-led invasion against Iraq, and becoming one of President George W. Bush's staunchest international allies.
Blair told Amanpour he feels an "enormous responsibility" for lives lost in Iraq. But he stood firmly by his decision to support Bush even though weapons of mass destruction were never found and the Iraq war led to a drain on resources in Afghanistan.
"You would be inhuman if you didn't regret the death of so many extraordinary, brave and committed soldiers, of civilians that have died in Iraq, or die still now in Afghanistan. And of course you feel an enormous responsibility for that, not just regret," Blair told "This Week's" Amanpour.
"But in the end, I believed and still do that if we left Saddam there, we would have had a different sort of problem, also with consequences and also with many people dying. So that's the difficulty for me, and likewise in Afghanistan," he added. "I think if we hadn't taken on the Taliban and hadn't taken on what had been a training ground for al Qaeda, we would be in trouble."
Hussein couldn't be contained, Blair argued, and even though it might have been better to focus on Afghanistan first, the former prime minister said world leaders couldn't take that risk.
"I don't know, and you don't know, and you're making a calculation of risk," he said. "And the thing is, when you're sitting in the hot seat of decision making, you've got to decide."
Blair wouldn't rule out an attack against Iran if he was leading the country and was faced with the threat of Iran acquiring a nuclear weapon.
"I would tell them they can't have it, and if necessary, they will be confronted with stronger sanctions and diplomacy. But if that fails, I'm not taking any option off the table," he said.
"When you're a leader sitting in the hot seat having to take the decision, supposing your worst case materializes," and Iran acquires nuclear capability and then decides to use it, or share that technology with someone else, "Then what?"
Blair's book, "A Journey: My Political Life," will be released in the United States later this week. It is already No. 1 on Amazon UK's Bestseller list.
The former prime minister is in the United States to participate in the Middle East peace talks.