POLITICIANS should have learnt by now that metaphor and mass suffering do not mix - or, at the very least, that the public is suspicious of verbal wit when times turn cruel. Douglas Hurd was forcibly reminded of the fact last week when he replied to Baroness Thatcher's operatic intervention on the Bosnian crisis.

Arming the Muslims, he said, would merely create a 'level killing field', a clever conflation of two media cliches1 , which Lady Thatcher, in a brief encore the next day, described as 'disgraceful'. Others, too, picked it up as one of the Foreign Secretary's less felicitous moments, a remark he would live to regret.

But you can almost imagine the thought processes that went on when he (or his office) was asked to supply a response. 'What do I think of arming the Muslims? Well Bosnia would just become a killing field. Hmm . . . sounds a bit flat. Let's think - field, field . . . ploughed field? Open field? Playing field? Level playing field] That's it . . . Level killing field. Not bad at all.'

It was headline rhetoric, the sort of punning compression that virtually comes set up in 60-point type. There is a certain appropriateness in this; the phrase 'the killing fields' was first given wide circulation by Roland Joffe's movie about Cambodia, but David Puttnam, who produced the film, remembers it as having a journalistic origin.

The researcher working on the project had photocopied a heading from the New York Times ('Death in the killing fields of Cambodia') and attached it to the file she used for her notes. When Puttnam put the film into production the name, suitably shortened, stuck. What began life as a journalistic coinage2 , a grimly effective play on the murderous pastoralism of the Khmer Rouge, has returned as a sound bite.

Normally this would not matter. It has become almost a fixed habit of mind among the more practised politicians to speak in headlines. The problem was that Mr Hurd, along with the rest of the Government, apparently did not realise that he had entered a new realm of sensitivity - the public did not want verbal agility, it wanted emotion, and 'level killing field' smacked too much of being on the outside. The grim coincidence that real killing was taking place on Srebrenica's non-metaphorical playing field did not help.

The remark collapsed under pressure. Word play had seduced Mr Hurd into a moral absurdity. Are we really to take it that unlevel killing fields, in which one set of combatants enjoys an advantage in the slaughter, are preferable to the level kind? (This may be exactly what is meant. When ministers insist that such-and- such an action will 'only prolong the war' you can't help wondering whether this is a less obviously odious way of saying 'the sooner the Serbs win the sooner we can forget this mess'.)

Mr Hurd is not the first politician to have fallen foul of a trenchant phrase. 'At least Mrs Thatcher has got guts,' a heckler shouted at Neil Kinnock during the 1983 election. 'It's a pity', he snapped back, 'that people have to leave theirs on the ground at Goose Green in order to prove it.'

This is a slightly different case, in which indignation gets the better of a politician's circumspection, but the offence was similar. You could even argue that the subsequent row about flippancy had a lasting effect on Mr Kinnock's confidence in his own spontaneity and wit.

Four years later, on the eve of another election and just after the Zeebrugge disaster, the late Nicholas Ridley praised a colleague with the words 'He's not got his bow-doors open', a quip that typically prompted calls for resignation and, untypically, provoked an apology from Mr Ridley.

All three men forgot, through inadvertance, indignation or indifference, that death should alert wise politicians to purge their language of any trace of wit or verbal cleverness. We are resigned to politicians speaking in sound bites; we still want to believe that they don't feel in them, too.

1 From the French printer's term for a stereotype block made from a woodcut.

2 From the French coin, a wedge or die for stamping medals.