A man who kept the fragments of his life in different compartments until the end

There has been one great unspoken assumption shared by those who have had a part to play, or a comment to make, in the David Kelly affair. It is that criticising the late weapons inspector was somehow unfitting or indecorous. After all the man was dead. He may have had some faults, and made mistakes, but what greater price could he pay. Death wipes away many debts.

Those who tried to breach this unwritten law came a cropper, as with the infamous attempt by Downing Street to brand the scientist a Walter Mitty character. Or else they found their contribution disdainfully ignored, as with the attempt by "friends of Geoff Hoon" at the weekend to assert that 50 years ago Dr Kelly would have found himself being tried for treason.

Lord Hutton was polite in his critique of Dr Kelly. But it became clear from his report that Britain's leading expert on biological weapons had lied to a House of Commons select committee. He had probably lied either to a BBC Newsnight reporter or to his employers at the Ministry of Defence, or to both. And he was a man who told only part of the truth to his wife, family and friends.

Many will feel that his lies were understandable, if not to be condoned, as he found himself trapped in the turning cogs of the great political machine. He was a man who had given a lifetime of quiet dedication to the service of his country "in very difficult and testing conditions in Russia and Iraq", in the words of Lord Hutton. The current political fallout should not mask David Kelly's extraordinary achievements as a scientist and public servant.

There is even a sense, among the great sections of the population suspicious of the spin of politicians, that Dr Kelly was continuing this greater service in his "unauthorised" briefings to journalists - with the implicit insistence that intelligence should be impartial and not subject to the demands of politicians. Lord Hutton may have found that Andrew Gilligan embellished Dr Kelly's words, but the evidence that the scientist offered similar warnings to the BBC journalists Susan Watts and Gavin Hewitt is incontrovertible.

That such expert darts from the sidelines stung Downing Street was evident from its attempt to belittle him and portray him as a "middle-ranking official", a mere "technician" and "a junior source who could not have possibly known what was going on". One member of the Cabinet even referred to Britain's foremost expert on biological and chemical warfare as "a Dr Shipman-lookalike".

But the Government, as Lord Hutton has pointed out, are all honourable men. There was nothing "dishonourable, underhanded or duplicitous" in the way the scientist was treated and his identity tossed to the media. This is not quite how Dr Kelly's family see things, as was evidenced in their restrained observation yesterday that the law lord's findings "differ in part from their submissions to him". But the truth about David Kelly, the inquiry and the report show, is hard to piece together.

He was a man who kept the fragments of his life in different compartments. He occupied twin worlds, one commentator said: one of desert, dictatorship, biological warfare and interrogation, which was entirely his own; and the other the English village life of pub lunches, cribbage and walks in the countryside with his family.

But there was more to it than that. In the pub he did not drink alcohol after converting to the Bahai faith, an offshoot of Islam which also draws on Christianity, Judaism, Buddhism and Zoroastrianism. Yet he rarely talked about his exotic new faith to his wife, Janice. He was away a lot, sometimes in the company of female friends, such as Mai Pederson, an Arab-American military linguist, with whom the tabloids had a field day with far-fetched stories that she was a spy and/or Dr Kelly's lover.

There was a lot the Kellys did not talk about. "He would never tell me the nature of his meetings," Mrs Kelly told Lord Hutton. And his sister told the inquiry how, a decade ago, she was reading the obituary of a Russian microbiologist who had defected and asked Dr Kelly if he had heard of him. It turned out Dr Kelly had spent weeks in a hotel interrogating him, but had never mentioned it at home.

Yet his wife knew clearly enough that Dr Kelly felt "totally let down and betrayed" by the MoD. If he said little he was obviously "desperately unhappy about it", she said, "really, really unhappy about it, totally dismayed". There were vague threats of dismissal or a reduced pension.

And if David and Janice Kelly did not seem to exchange many words on some subjects, she could read his unhappiness in the "rather lacklustre way" he dug his vegetable patch - or the way, on the morning of his death, he sat slumped in an armchair in the living room in the late morning, when normally he would have been busy at his desk. Mrs Kelly looked at her husband of 35 years and had the sudden sense that "he had a broken heart".

The man who made his international reputation as a weapons inspector by catching out Russians and Iraqis in their lies and deceptions had become impaled upon his own.

In his summary statement yesterday, Lord Hutton sought explanation for this in the judgement of one of the inquiry's witnesses, Keith Hawton, professor of psychiatry at Oxford. What factors may have contributed to the death of this very private man?

"Severe loss of self-esteem, resulting from his feeling that people had lost trust in him and from his dismay at being exposed to the media," the psychiatrist said. "Being such a private man, this was anathema ... he would have seen it as being publicly disgraced. He must have begun to think that the prospects for continuing in his previous work role were diminishing very markedly. That would have filled him with a profound sense of hopelessness - that his life's work had been totally undermined".

Of course, yesterday the principle of political decorum held fast. Tony Blair, in his cocky apologia from the Commons dispatch box, found time to praise Dr Kelly as "a decent man whose very decency made him feel wretched about the situation he found himself in". And Michael Howard began his blustering rejoinder with orotund phrases about "a fine public servant who did an immense amount of public good for this country".

There must have been something vaguely sick-making about it all for the Kelly family. A quick genuflection and then the political caravan moves on, with the dogs barking at its heels.

We must leave the family to grieve in private, the Prime Minister said. Easier said than done. On Tuesday three consultant physicians raised doubts about the physiological adequacy of the explanation of the cause of death given to Lord Hutton. The pain of sudden death is bound up with the lack of resolution. The idea that it might not be suicide can only have exacerbated the black swirl of emotions in which Mrs Kelly and her daughters are enveloped. For them, Lord Hutton has brought no easy conclusions.