Dr David Kelly: Betrayed. Let down. Anxious. Hurt. Exhausted. Desperate. Heartbroken.

The words Janice Kelly used to describe her husband in the last days of his life

In the final hours before her husband left their home for the last time, Janice Kelly could no longer bear his desolation. "I was physically sick several times because he looked so, so desperate," she recalled yesterday. "He was distracted and dejected. He looked really very tired. He had shrunk into himself, just shrunk. But I had no idea what he might do later."

A little later Dr David Kelly went off for his walk, a broken man, betrayed and belittled, he believed, by the state he had served over so many years. Swatted away at the end, he said, "like a fly". Mrs Kelly was told in the early hours of the next morning that he had been found dead with his wrist slashed.

It should have been the best of times for Dr Kelly, looking forward to returning to Iraq for unfinished business, the hunt for Saddam Hussein's suspected arsenal of weapons of mass destruction; the chance of a prestigious post in the United States after his impending retirement; and the prospect of a knighthood to add to the CMG already awarded for his work.

Instead, Mrs Kelly had seen his life disintegrate in the space of a few weeks as he became caught in the bitter confrontation between Downing Street and the BBC over claims that the Government's dossier on Iraq was "sexed up".

Yesterday, at the Hutton inquiry, she spoke for the first time of how the treatment her husband had received had "broken his heart". He had felt "totally let down and betrayed" by the Ministry of Defence at the way his identity was confirmed to the media, and how he was delivered for questioning to two separate committees of MPs, one of them in the full glare of television cameras.

Mrs Kelly gave her evidence on an audiolink into court 73 at the High Court, just a photo of her face on a screen. It was the most personal and emotive testimony heard so far, and, for Downing Street, devastating.

At the time of Dr Kelly's death, Tony Blair is said to have acknowledged privately that if the scientist's family blamed his Government over what happened, his position would be called into question. That damning accusation was made six weeks later. Mrs Kelly told the inquiry that when her husband had come forward to tell his superiors at the MoD that he had met the BBC journalist Andrew Gilligan, he was assured that his identification would not be made public.

Extraordinarily, while the honours section in Downing Street was considering whether Dr Kelly should be offered a knighthood, Mr Blair's official spokesman was claiming that the MoD rated his contribution as no more than that of a "middle-ranking technical expert". Mrs Kelly said: "He was deeply, deeply hurt. He was being treated like a fly, that's the phrase he used."

Dr Kelly had "gone ballistic" when told by his bosses at the MoD that he must give evidence at the public hearing at the Foreign Affairs Committee. Mrs Kelly said: "I have never seen him, through all his time in Iraq, where he has faced lots of horrors and guns being pointed at him, I have never known him to be as unhappy as he was then, it was tangible."

The MoD, Mrs Kelly said, left her husband isolated, without any support. He became deeply upset when a journalist arrived at his home in Oxfordshire, uninvited, to say that his name was being made public. The anxiety heightened when the MoD telephoned to say that the couple had five minutes to leave their home before large numbers of journalists would begin to arrive.

Being asked to give evidence before the Foreign Affairs Committee was particularly upsetting for Dr Kelly. Mrs Kelly told the hearing that as the pressure mounted she and her husband became "exceedingly upset, we were both very, very anxious, very stressed ... It was just a nightmare, that's all I can describe it as." All the time, there was denigration from the Government - "there were comments about his junior status, it was just belittling".

After being told to leave their home, without anyone coming down from the Ministry of Defence to offer advice, the Kellys packed within 10 minutes and headed for Cornwall. Mrs Kelly said: "He looked totally exhausted, he was able to converse a little, but it was very, very strained. I felt he was very, very tired, used up."

She recalled the night he went missing. "We delayed calling the police because it might make matters worse if David returned when they had started a search. He was already in a difficult enough situation. I was in a terrible state myself at the time, trying not to think awful things and trying to take each moment as it came."