Iraq is Tony Blair's war. He should now do the honourable thing and resign

I believe he should accept responsibility for one of the worst foreign policy disasters the country has ever experienced

For the first time in my life, I am ashamed of my country's leader. This is nothing to do with domestic policies. I have twice voted for New Labour. I even saw a similarity between New Labour and The Independent. Both were founded to breathe new life into old forms. No, the issues which afflict the heart are the presentation of a misleading case for war and then the sending British soldiers to their deaths for nothing. At the same time, British influence in the world has collapsed and the relationship with President Bush has been humiliating

The Iraq war is Tony Blair's war. For how often and how seriously the Prime Minister was warned against it. Some 2 million British people marched in protest. In the House of Commons, 139 Labour MPs voted against. Nato did not support war, neither did the European Union nor the Security Council. Six months before the march, Jonathan Powell, the Prime Minister's chief of staff, referring to a draft of the famous September dossier, had advised: "the document does nothing to demonstrate a threat, let alone an imminent threat from Saddam". And Mr Powell added: "we will need to make it clear in launching the document that we do not claim that we have evidence that he is an imminent threat." But shortly after this message was sent, the Prime Minister wrote a foreword to the final version of the same dossier in which he stated: "I have no doubt the threat is current and serious." The dossier, too, was Mr Blair's dossier and nobody else's.

Then a few weeks before hostilities commenced came a warning from the Joint Intelligence Committee. It told Mr Blair that "there was no intelligence that Iraq had provided chemical or biological materials to al-Qa'ida or of Iraqi intentions to conduct chemical or biological attacks using Iraqi intelligence officers or their agents." Its conclusion was that any collapse of the Iraqi regime would increase the risk of chemical and biological warfare technology or agents finding their way into the hands of terrorists. The Prime Minister took no notice.

Two Cabinet colleagues, Clare Short and Robin Cook, objected. At the same time, just before war began, Mr Blair received a personal minute from Mr Cook's successor at the Foreign Office, Jack Straw. It urged the Prime Minister to consider an alternative strategy. Britain would offer the United States full political and moral support, we would deploy troops at the end of the war for peace enforcement but we would not go to war. To Mr Straw and all other doubters, whether marchers, allies, Cabinet colleagues or even his own staff, the Prime Minister responded: sorry, I am right; you are wrong. This is what I believe.

Yet to strengthen his case, this true believer also felt the need to have rewritten the advice received from the Joint Intelligence Committee. In this way, by altering the words, Mr Blair changed the assessment. Thus the September dossier, solemnly presented to the British people as the intelligence services' considered view, was rendered misleading. The country was allowed to draw the erroneous conclusion, for instance, that British bases in Cyprus were at risk from long-range weapons of mass destruction that could be deployed in 45 minutes.

Finally, when he spoke to the House of Commons on the eve of war, Mr Blair quoted material that supported his case, but failed to mention the recent intelligence warning that attacking Iraq would make matters worse rather than better. This was deceitful, and comes as close to lying to Parliament as makes no difference.

With this background, it is not surprising that events have proved Mr Blair completely wrong. The September dossier was mistaken in almost everything it stated. It was the most worthless state paper ever published. In particular, no weapons of mass destruction were used. None have been found. No evidence that Iraq continued to work on its nuclear programme has turned up.

At least, we are told, Saddam Hussein and his regime, butchers of the Iraqi people, have been removed. "History," says the Prime Minister "will forgive us." But will it? Now there are many warlords rather than one. Iraqis feel even less secure than they did. For a murderous government was a known quantity. In theory people could plan their lives to keep out of its way. Anarchy, on the other hand, is more terrifying. For the assassins' bullets, the quasi-judicial murders, the everyday killings, the brutal beatings, the abductions and the thievings are, by definition, unpredictable. In Baghdad there has been a 25-fold increase in gun-related killings since the invasion.

Moreover the Iraqi war continues. The terrorists' ends are to prevent the coalition from reconstructing the country along Western lines. Their means are slaughter and destruction. This is why American soldiers are killed every day so that they patrol ever closer to their barracks. This is why members of the Governing Council are murdered so that no American sponsored administration can get going. This is why oil pipelines are consistently ruptured so that the huge costs of the occupation fall on American and British taxpayers. This is why the United Nations building was blown up so that no international solution is possible. It is all of a piece; it is coherent; it is war.

The charges against the Prime Minister are exceptionally grave. The first one is this. Mr Blair has blood on his hands for sending British troops to their deaths on a misleading assessment. To find something which wasn't there. After withholding crucial information from a Parliamentary debate in order to gain the approval of MPs. Second, British interests have been badly served. The Prime Minister has led the nation into a quagmire in Iraq from which it will be very difficult to emerge with credit. Third, Mr Blair has diminished British influence. We no longer have much say anywhere, scarcely in the White House, hardly at all on this side of the Atlantic. Is this why Mr Blair didn't go to the annual meeting of the UN in New York last week, even though the leaders of the United States, Germany and France were present? Rather than being at the heart of Europe, we are further out on the periphery than we have ever been.

Fourth, the Prime Minister has humiliated us. He has faithfully served the wishes of a US administration whose neo-conservative views command little support in this country. He has left us at risk in Iraq with no alternative but to follow wherever American policy leads. We are trapped without control of our own destiny.

I believe that Mr Blair should honourably accept responsibility for one of the worst foreign policy disasters which the country has ever experienced, and resign forthwith. I impatiently count the days, weeks, months and perhaps, alas, years until Mr Blair goes.