Tony Blair: 'It is my task to expose the global threat, whatever the political cost'

This is an edited version of Tony Blair's speech yesterday:

No decision I have ever made in politics has been as divisive as the decision to go to war to in Iraq. It remains deeply divisive today. I know a large part of the public want to move on.

But I know, too, that the nature of this issue over Iraq, stirring such bitter emotions as it does, can't just be swept away as ill-fitting the preoccupations of the man and woman on the street.

This is not simply because of the gravity of war; or the continued engagement of British troops and civilians in Iraq; or even because of reflections made on the integrity of the Prime Minister.

It is because it was in March 2003 and remains my fervent view that the nature of the global threat we face in Britain and round the world is real and existential and it is the task of leadership to expose it and fight it, whatever the political cost.

And that the true danger is not to any single politician's reputation but to our country if we now ignore this threat or erase it from the agenda in embarrassment at the difficulties it causes.

Each week brings a fresh attempt to get a new angle that can prove it was all a gigantic conspiracy.

Most recently is the attempt to cast serious doubt on the Attorney General's legal opinion. But let's be clear. Once this row dies down, another will take its place and then another and then another.

All of it in the end is an elaborate smokescreen to prevent us seeing the real issue: which is not a matter of trust but of judgement. Iraq in March 2003 was an immensely difficult judgement. It was divisive because it was difficult.

There was a core of sensible people who faced with the decision would have gone the other way, for sensible reasons. Their argument is one I understand totally.

It is that Iraq posed no direct, immediate threat to Britain; and that Iraq's WMD, even on our own case, was not serious enough to warrant war, certainly without a specific UN resolution mandating military action. And they argue: Saddam could, in any event, be contained.

In other words, they disagreed then and disagree now fundamentally with the characterisation of the threat

Of course the opponents are boosted by the fact that though we know Saddam had WMD, we haven't found the physical evidence of them in the 11 months since the war. But, in fact, everyone thought he had them. That was the basis of UN Resolution 1441.

But the key point is that it is the threat that is the issue. The characterisation of the threat is where the difference lies. Here is where I feel so passionately that we are in mortal danger of mistaking the nature of the new world in which we live.

The threat we face is not conventional. It was defined not by Iraq but by 11 September. That day did not create the threat Saddam posed. But it altered crucially the balance of risk as to whether to deal with it or simply carry on, however imperfectly, trying to contain it.

11 September was, for me, a revelation.

Here is the crux. My judgement then and now is that the risk of this new global terrorism and its interaction with states or organisations or individuals proliferating WMD, is one I simply am not prepared to run.

This is not a time to err on the side of caution; not a time to weigh the risks to an infinite balance; not a time for the cynicism of the worldly wise who favour playing it long.

Their worldly wise cynicism is actually, at best, naivete and, at worst, dereliction. When they talk, as they do now, of diplomacy coming back into fashion in respect of Iran or North Korea or Libya, do they seriously think that diplomacy alone has brought about this change?

Yet it is monstrously premature to think the threat has passed. The risk remains in the balance here and abroad.

Sit in my seat. Here is the intelligence. Here is the advice. Do you ignore it? But, of course intelligence is precisely that: intelligence. It is not hard fact. It has its limitations. But in making that judgement, would you prefer us to act, even if it turns out to be wrong? Or not to act and hope it's OK? And suppose we don't act and the intelligence turns out to be right, how forgiving will people be?

I have no doubt Iraq is better without Saddam; but no doubt either, that as a result of his removal, the dangers of the threat we face will be diminished.That is not to say the terrorists won't redouble their efforts. They will. This war is not ended. It may only be at the end of its first phase.

Containment will not work in the face of the global threat that confronts us. The terrorists have no intention of being contained. Emphatically I am not saying that every situation leads to military action. But we surely have a duty and a right to prevent the threat materialising; and we surely have a responsibility to act when a nation's people are subjected to a regime such as Saddam's.

I understand the worry the international community has over Iraq. It worries that the US and its allies will by sheer force of their military might, do whatever they want, unilaterally and without recourse to any rule-based code or doctrine. But our worry is that if the UN - because of a political disagreement in its Councils - is paralysed, then a threat we believe is real will go unchallenged.

This dilemma is at the heart of many people's anguished indecision over the wisdom of our action in Iraq.

It means reforming the United Nations so its Security Council represents 21st century reality; and giving the UN the capability to act effectively as well as debate

But in the meantime, the threat is there and demands our attention.

It is a new type of war. It will rest on intelligence to a greater degree than ever before. It demands a difference attitude to our own interests. It forces us to act even when so many comforts seem unaffected, and the threat so far off, if not illusory.

In the end, believe your political leaders or not, as you will. But do so, at least having understood their minds.