According to Professor Julian Perry Robinson, Britain's most senior and respected expert on chemical weapons and a friend and colleague of Kelly's, these experiences hardened him.
It seems unlikely that a man with his background would have been driven to suicide by one or two bumptious members of the parliamentary foreign affairs committee, unpleasant though he clearly found his public grilling by the MPs.
Friends and fellow scientists have speculated that he came under heavy pressure in Whitehall once he had admitted giving an unauthorised interview to BBC journalist Andrew Gilligan. But he was an experienced bureaucrat who had been spied on and bullied by far more menacing people than the mandarins of the Ministry of Defence.
One important piece of evidence that has been overlooked, however, is that Kelly, once known as one of the more hawkish UN inspectors in Iraq, appeared to have changed his views in the past couple of years. "Because of the way they were treated by the Iraqis, most UN weapons inspectors were convinced that Saddam Hussein had something to hide," said one analyst.
"Not only did he speak quite frequently about the difficulties the inspectors faced, he emphasised that the Iraqis had vast quantities of chemical and biological material before the 1991 Gulf War."
He was senior adviser on biological weapons to Unscom, the UN weapons inspectorate, until 1999. That year he took on a similar role as a consultant to the MoD and the Foreign Office.
In April last year, when the Government began looking for experts to contribute to a dossier on Iraq's weapons of mass destruction, it seemed natural for it to call on Kelly.
What the Government might not have known was that a month earlier, at a seminar at University College London, the scientist had signalled a change of heart.
Throughout the 1990s, he said, UN inspection teams had found no definite evidence of any ongoing chemical or biological programmes in Iraq.
"Having agreed to take part in what he believed would be an objective assessment of the state of Iraq's [weapons of mass destruction], it is possible that he became disillusioned as the process went on," said the analyst.
"Initially the Government was talking about releasing a dossier very quickly, but it was six months before it was finally issued in September 2002, with highly contentious allegations, especially the claim that Saddam could launch weapons within 45 minutes of the order being given.
"For a man who knew this was nonsense, it must have been a severe strain. For professional reasons he had to put out statements in which he didn't have any faith."
Even if he was not Gilligan's source for the claim that the Prime Minister's communications director, Alastair Campbell, inserted the 45 minutes claim to "sex up" the dossier, Kelly's doubts were communicated to Gilligan and other journalists. He told them and the foreign affairs committee that there was only a 30 per cent chance that Iraq still had biological weapons at the beginning of the war.
But on July 3, as the row between Campbell and the BBC over the allegation heated up, a troubled Kelly came forward to his line manager.
According to the Government, he had been worried by press reports of the saga because he had met Gilligan in London on May 22, a week before the journalist made his allegation.
Although Kelly was convinced that he was not the source, he was anxious because some of the points covered in their discussion featured in Gilligan's reports.
MoD officials questioned Kelly, in line with the department's normal practice on personnel matters.
Downing St is adamant that it was not involved. Kelly and the MoD agreed that a statement would be issued that would not name him, but would say that an official had come forward to admit he had held an unauthorised conversation with Gilligan. No 10 approved the move.
According to Downing St, Kelly was warned that it was "quite likely" his name would become public, because there were relatively few people working in his field. He was also told he might be asked to give evidence to the intelligence and security committee, which monitors the security services.
The statement about the conversation with Gilligan was not issued until five days after Kelly came forward. Whitehall says the delay was due to the need to assess whether he might be Gilligan's source.
But some senior Whitehall sources say Kelly was interrogated "brutally" in that time.
Sources say he was threatened with being charged under the Official Secrets Act.
As the furore over the US and Britain's weapons claims rumbled on, months after the end of the war, Kelly must have felt his reputation was at stake.
As more time elapsed without any evidence being found in Iraq to prove the Government's claims, a man who had invested much of his life in discovering the truth about Iraq's weapons of mass destruction found himself associated with a campaign that appeared further and further from the truth.
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INDEPENDENT
Death of a civil servant, a casualty of war
British Parliament Foreign Affairs Committee transcript:
Evidence of Dr David Kelly
Key players in the 'sexed-up dossier' affair
Herald Feature: Iraq
Iraq links and resources
