ROBIN Cook portrays himself as a man of deep-rooted political and moral conviction.

When he became Foreign Secretary in 1997, he set himself very high standards. Famously, he promised to give British foreign policy an "ethical dimension".

Even the disclosure that British arms were being exported to Indonesia and used to crush the uprising in East Timor failed to persuade him to dilute his principles.

To the casual observer his decision to resign from government over the issue of the looming war against Iraq therefore displays a consistency and honour often lacking in modern politics.

Privately, he has told the Prime Minister of his opposition to taking military action without support of the United Nations. And once it became clear that unilateral action was imminent he feels he can no longer be bound by the restrictions of Cabinet responsibility.

Mr Cook's stance, however, fails to take account of the reality of the current situation.

The Prime Minister has been resolute in his efforts to secure a second resolution on Iraq from the UN Security Council.

Tony Blair and George Bush have not deliberately sidelined the UN in their approach to Iraq. It is the UN which has chosen to duck the issue and avoid dealing with the crisis.

It is difficult to envisage Mr Cook acting any differently to Mr Blair or Jack Straw had he still been at the Foreign Office, facing the grim reality that the faith placed in the UN to impose the will of the international community has been misplaced.

This is a man who, after all, was prepared to support intervention in Bosnia without the approval of the UN.

Mr Cook, moved against his wishes from the Office in 2001, is no longer the key figure he once was in the New Labour hierarchy.

There is a suspicion, therefore, that there is more to his resignation that just the Iraq crisis.

Sidelined from the major affairs of state with little prospect of promotion, it is feasible that Mr Cook has taken this opportunity to quit with his honour intact, and at the same time inflict damage on the Prime Minister who robbed him of the job he loved.