Hans Blix has just renewed his contract as chief UN weapons inspector for Iraq until the end of June. He says that summer would be a nice time to return home to Sweden. Why wait, Hans? You can resume your retirement at your retreat on the Baltic island of Graesoe in time for spring. It is time to resign.

Dr Blix’s recent performance has not only discredited himself but has betrayed the trust of all those many millions around the world who put their faith in the United Nations. Worse, his disingenuousness has guaranteed that the world’s sole remaining superpower will never put its security in the hands of a multilateral inspection agency because he has proved it is unreliable. He was hired as a technocrat and seems to have been behaving like a politician.

Resolution 1441 asks the chief inspector to answer a single question: is Iraq co-operating fully? Dr Blix refuses to give a simple answer to this question because he knows what that answer would be. When I asked him it last week, he explained: “There are lots of questions in this world, Mr Reporter, to which you should not answer ‘yes’ or ‘no’.”

But this is not “Have you stopped beating your wife?” This is the question he was hired to answer. In his press conference on Thursday, President Bush pushed Dr Blix for a “yes” or “no” answer, too. The next day, Dr Blix took five sentences to give his response.

I am not a UN-hater, nor a Blix-hater. I have reported on the UN for 15 years, and over the past six months, following Dr Blix’s actions, I have observed its affairs almost minute by minute. I find him a likeable and, in his personal conduct, an admirable man. If he had succeeded in supervising the disarmament of Iraq, I would be the first in line to cheer him on. So what went wrong?

Dr Blix’s position is defined by two poles: on the one hand he clearly believes that Iraq should disarm voluntarily, leading inspectors to its hidden stockpiles of chemical and biological arms. He was the man who, as head of the International Atomic Energy Agency, oversaw the nuclear disarmament of South Africa. In 1994 the South African Government presented him with a sculpture of a ploughshare made from a piece of a bomb. He would clearly like Saddam Hussein to do the same.

At the same time, however, Dr Blix is apparently determined that he will not be the man who triggers war. To put it simply, he does not want to be Richard Butler, his predecessor, who was blamed for precipitating the 1998 air campaign against Iraq. This imperative has led him astray.

Although he “emphatically” denies he is keeping information from the Security Council, his direct employer, he has been burying it. Instead of telling Security Council foreign ministers last Friday that he had found an undeclared Iraqi drone, he just criticised the United States for giving him bad intelligence and slipped the revelation about the drone into an update to a 173-page report distributed after the meeting. He also failed to mention until the report the discovery in December of modified “drop tanks” that can be used for spraying chemical or biological agents. The report speaks of aerosol generators and says “evidence of ‘parallel’ work on a similar device that was not declared is of some concern.” By failing to alert the world, Dr Blix has allowed Iraq to perpetuate the “Big Lie” that it is weapons-free.

When the history of this tumultuous time is written, Dr Blix will be the man who tried to hide the “smoking gun”. For those who saw him as their favourite Swedish uncle, an anchor in the storm, this has been a truly shocking — and disappointing — revelation.