On Tuesday he gave evidence to a committee of MPs, speaking in a barely audible voice and looking ill at ease. By yesterday the body of Dr David Kelly was discovered by the police. It is unimaginably disturbing news, even by the standard of contemporary politics, which is a notoriously rough game.

The brute truth of unexpected death has intruded itself on politics. It is a reminder that, however much some of the participants relish the cut and thrust of accusation and counter accusation, it is not a game at all. For weeks now, we have listened as ministers, advisers and journalists slug it out, refusing to back down and becoming ever more polarised. There have been spats on radio and TV, furious exchanges of letters between the BBC and the Government, sides taken and trenches dug, and lots of scenes in which extremely opinionated men shout down other extremely opinionated men.

At the heart of it is a genuine moral question, whether the Government “sexed up” its September dossier on Iraq’s military capability in order to justify an unpopular war. But yesterday’s turn of events raises other moral issues about standards of behaviour in public life, not least whether it is reasonable to treat ordinary individuals such as Dr Kelly as roughly as politicians and journalists, who are accustomed to toughly handling each other.

When the junior minister Ben Bradshaw locks horns with John Humphrys, or a Downing Street official fires off an intemperate letter to the BBC, there is a tacit assumption that we are witnessing a species of performance. We may not like it — for some time now, I have had the impression that the public’s reaction to the twists in the WMD affair has been boredom on the one hand and irritation on the other — but we do not really imagine that Mr Bradshaw or Mr Humphrys retreats to his office afterwards, stunned and shaking. We may wish the whole row would go away, at least until someone had something new to say, but there is also an assumption that the people involved can take it, that their hides are rhino-thick.

On Tuesday, when Dr Kelly gave evidence to the Foreign Affairs Select Committee, something changed. A patently honourable and decent man had been dragged into a bearpit. It was clear from his demeanour that he was there very much against his will and was hating every moment of it.

Admittedly Dr Kelly, an adviser in the Ministry of Defence’s proliferation and arms control secretariat, had volunteered the information to his bosses that he had talked to the BBC defence correspondent, Andrew Gilligan, a week before the latter’s contested report was broadcast on the Today programme. But it seems unlikely that Dr Kelly anticipated the consequences of his honesty.

Not only was he very publicly identified by the Government as Mr Gilligan’s source, a claim he disputed, but he was asked by MPs to account for actions that must have seemed harmless to him at the time. It is not even as if the select committee, with its built-in Labour majority, is a neutral forum, and one of its members was probably right to suggest that the unfortunate Dr Kelly had been thrown up as a “chaff”.

It never seemed likely that either of the parliamentary committees inquiring into the WMD affair would come up with an impartial report. Too much is at stake and we have now seen the folly of allowing contentious events — with perhaps even the capacity to bring down the Prime Minister — to be investigated by people who are politically partisan. The case for an independent inquiry, empowered to take evidence in a calm, forensic atmosphere, away from the overheated exchanges of Westminster, is overwhelming.

But the larger lesson of yesterday’s grim news is that the macho, brawling style of politics is not the victimless sport its participants fondly imagine. It is unpopular with the public, it obscures important issues and the personal cost is much higher than anyone anticipated. This is a moment to think again about the way we conduct disagreements in this country, and the potentially disastrous effects on individuals who find themselves thrust into the political arena.

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