Blair defended his decision to support the United States in the aftermath of the attacks of September 11, 2001, including going to war against Iraq in 2003.

In a personal speech at the Trimdon Labour Club in the north-east constituency of Sedgefield he has represented since 1983, Blair said Britain had changed for the better since he took over as premier in 1997.

But there were difficult decisions along the way, particularly when there was widespread opposition, leading to his fiercely-held conviction to be misinterpreted as "messianic zeal", he added.

"Doubt hesitation reflection consideration reconsideration these are all the good companions of proper decision-making but the ultimate obligation is to decide," he said.