In an extraordinary departure from the diplomatic language with which he has come to be associated, Mr Blix assailed his critics in both Washington and Iraq.
Speaking exclusively to the Guardian from his 31st floor office at the UN in New York, Mr Blix said: "I have my detractors in Washington. There are bastards who spread things around, of course, who planted nasty things in the media. Not that I cared very much.
"It was like a mosquito bite in the evening that is there in the morning, an irritant."
In a wide-ranging interview Mr Blix, who retires in three weeks' time, accused:
·The Bush administration of leaning on his inspectors to produce more damning language in their reports;
·"Some elements" of the Pentagon of being behind a smear campaign against him; and
·Washington of regarding the UN as an "alien power" which they hoped would sink into the East river.
Asked if he believed he had been the target of a deliberate smear campaign he said: "Yes, I probably was at a lower level."
Before he had even flown to Iraq to relaunch the sensitive weapons inspections after a four-year hiatus last November, senior US defence department officials were excoriating the septuagenarian as the worst possible choice for the post.
It was just the beginning. By autumn, the happily married father of two was being branded in Baghdad as a "homosexual who went to Washington every two weeks to pick up [his] instructions".
"The Iraqis were spreading that rumour about me early in the autumn and then I heard the counter-rumour that I had told my wife, Eva, about this rumour and that she said she had never noticed it. My alleged comment to her," he said, breaking into laughter, "was that nor had I." But the criticism clearly hurt.
A lot of the sniping "surely came" from the Pentagon, said Mr Blix, who has since won plaudits for his handling of the unenviable brief of divining whether Iraq had disarmed.
Staff attached to the UN monitoring and inspection commission, headed by the Swede for the past three years, openly say there is no love lost between hawks in the Bush administration and their mission.