Heckler fails to ruffle Blair's lawyerly calm

LONDON (Reuters) - A heckler shattered the calm when former Prime Minister Tony Blair told Britain's Iraq War inquiry that he had no regrets over the ousting of Saddam Hussein in the U.S.-led invasion of 2003.

A male voice shouted out in anger as Blair made his comments at the end of six hours of televised testimony to the public inquiry seeking to learn the lessons of the war.

Blair's appearance in a small conference center room in Westminster was the hottest ticket in town -- the 60 seats were allocated by ballot and given to relatives of some of the 179 British soldiers killed in Iraq.

"This is not a trial," inquiry chairman John Chilcot told the audience at the start of the day, asking them not to disrupt proceedings.

At times it felt more like a legal masterclass as Blair, 56, drew on his professional training to give a calm, measured performance.

Wearing a dark blue suit and red tie, Blair initially appeared nervous but was swiftly into his stride.

Consulting a thick set of notes in a ring binder, the man who governed Britain for a decade until stepping down in 2007 explained how the Sept 11, 2001 attacks on the United States had changed "the calculus of risk" about Iraq.

That elegant lawyerly phrase set the tone for what was to follow.

Blair, now a Middle East envoy with a lucrative set of corporate roles, handled questions from the five-person panel confidently, speaking fluently and with little outward sign of emotion beyond the occasional twitch of his jaw.

Panellist Roderic Lyne, former ambassador in Moscow, deferred to Blair's legal knowledge at one point when trying to summarize testimony on the legality of the war.

"I'm not the lawyer, you are," said Lyne, normally one of the more aggressive members of a panel criticized in some quarters for its soft questioning.

Rose Gentle, whose 19-year-old son Gordon was killed in Basra in 2004, sat a few yards from Blair during the morning session.

"You could see his hands shaking. He was clearly a bit nervous," she said.

Gentle said she had little interest in Blair as an individual. "I couldn't give a damn what happens to that man. I want lessons to be learned."

(Additional reporting by Girish Gupta, editing by Tim Pearce)