IF it were the official policy of the West to depose tyrannical dictatorships, we would be at war with dozens of regimes across the globe.

The debate on what to do with Iraq is not over whether Saddam Hussein is good or evil. Even the staunchest opponents of military intervention will still be overjoyed to see him toppled.

The debate is over whether there is legitimate grounds for intervention to end his reign of terror.

Britain and America can't have it both ways. They cannot preach the virtues of internationalism embodied in the United Nations one day, and then the next day unilaterally embark on a crusade against tinpot dictatorships.

The world has moved on since the days when Britain, and later the United States, were able to call themselves the policeman of the world and act accordingly.

If, as he declared yesterday, the Prime Minister has incontrovertible evidence that Saddam Hussein is developing a chemical, biological and nuclear arsenal, then it must be made public.

To stand idly by while Iraq is arming itself to the teeth will indeed by utterly irresponsible.

But the evidence must be presented to the British people, for them to determine whether the case for the use of British armed forces against Iraq is justified.

And it must also be presented to the UN, for the international community to determine whether military action is justified.

It is infinitely more preferable for any action to have the support of the UN, than for the United States and Britain to go it alone.

Presenting the evidence is a high risk strategy, but one the Prime Minister must pursue. Without publication of the case against Saddam Hussein, Mr Blair risks being portrayed as President Bush's poodle.

Without the full support of British public opinion, he will find it extremely difficult to order British forces into action.

And without the full support of the UN, both he and President Bush may destroy the fragile coalition against terror which has been preserved since September 11.

At all costs we must avoid the scenario of ridding the world of one menace, only to create many more.