My part in lain Duncan Smith's sullen, sarcastic and ill-tempered outburst

am Duncan Smith and his party have thrown two big wobblies about BBC coverage in recent weeks. One episode occurred in the small hours of Friday 2 May when David Dimbleby compered BBC Television's localelection-night programme. The other unfolded last Sunday lunchtime on Radio Four's The World This Weekend as the presenter, James Cox. took a look at the Tories' postlocal-election prospects.

Min Duncan Smith is furious about both broadcasts. As it happens, they have something in common: me.

But in each case I was little more than a chance witness. Hardly seen by the Tory leader as an exceptionally fearsome creature, I will feature in these complaints as no more than symptomatic of what the Tories think is wrong with the BBC. The Conservative party is right to feel occasionally niggled, wrong to think itself uniquely abused, right to keep up the pressure on the Corporation, but very wrong to let the leader himself get into scraps he should rise above.

First to David Dimbleby's programme. The results of May's local elections were just beginning to come in. In the BBC's Millbank studio at Westminster, Mr Dimbleby was chairing a big round table with a shifting miscellany of studio guests and commentary from Peter Snow and others elsewhere. Guests alongside me included Michael Howard (the shadow chancellor), Lord (Tom) McNally from the Liberal Democrats and someone from the Labour party — it was Tessa Jowell. From a street somewhere David Mellor briefly joined us, too. From time to time we would go over to an announcement at a local count.

Crispin Blunt's resignation from the Tory front bench was on every front page, not unreasonably. But first we looked at the handful of results already declared which (in my view) were not too bad for the Tories but did not guarantee the better news that was to come. What was already emerging was their percentage share of the vote, which was disappointing.

As a longstanding Tory myself, I said that it would be hard for any party to see these results as either triumph or disaster (a view I still hold). Tessa Jowell thought things were looking good for Labour. Tom McNally thought his party was doing better than the Tories. Michael Howard thought the Tories were doing splendidly. No surprises there. Mr Dimbleby chaired the discussion scrupulously and all were given their say, but most of us (not Mr Howard) wanted to talk also about Crispin Blunt's intervention. There was an extended discussion of this.

Michael Howard blew up. Waiting until we were temporarily off air, he made his complaint to Mr Dimbleby courteously but fiercely. This programme was supposed to be about the count, he said. Good news for his party was coming in from the count — so what did we do? Switch to a discussion of leadership woes.

I had suggested that the immediate news about Mr Blunt would die an early death, but dissatisfaction with Lain Duncan Smith would rumble on. David Mellor had struck a bitter note.

Mr Howard will not have known that the Daily Telegraph's Janet Daley, who would have been pro-IDS, had been engaged to appear but was then shunted to the second hour — which (I hear) she was unable to do.

One can understand Mr Howard's irritation. But Mr Blunt's resignation was a big story and not irrelevant to election night; and since it remains my view that leadership rumbles will continue — I do talk to Tory MPs — I cannot regret expressing it.

What, however, someone in my position does need to keep an uneasy eye out for is the possibility that broadcasters will use the voice of a known (but loose-cannon) supporter of a party as satisfying the quota for balance between parties but in a way which is in fact unhelpful to the party. I sometimes suspect the BBC of doing this, but more often in pursuit of mischievous fun than through partisanship. Mark Seddon is regularly hauled in, nominally as a 'member of Labour's National Executive Committee' but in fact to dish Tony Blair. Mark and I may even flatter ourselves that our opinions might occasionally be thought worth hearing for themselves, rather than for either balance or mischief.

I was mindful, though, of becoming a useful idiot when asked later to talk to The World This Weekend about Tory prospects. My view is that the party should be pretty sanguine about the local-election results. If you give a politician enough rope, he will hang himself, and I see a danger that as the Tories start to edge up in the polls Min Duncan Smith may suffer a rush of blood to the head and let a darker persona off the leash. I have been genuinely shocked by the low regard in which he is held by his parliamentary colleagues, and doubt that under him the party can hope for more than that he may keep his head and lead them at the next election to a less humiliating defeat than before. After that they will have to return to the leadership question.

said as much to James Cox in an interview pre-recorded last Friday, worrying a little about how my contribution might be used. But when I listened on Sunday I was content. Boris Johnson gave a stoutly loyal interview, balancing mine, Archie Norman (it is true) was less helpful, opining that the 'quiet' man might not be heard; but Mr Norman is a very senior figure in the party, and respected. All were Tory voices, and I regularly hear much ruder ones when I talk to Mr Duncan Smith's own colleagues.

This may explain the opposition leader's cold fury when Mr Cox's interview with him (for which our contributions were preparatory) began. But it was extraordinarily badly judged. He was sullen, sarcastic and ill-tempered, returning again and again to attack the programme and the Corporation's 'agenda'. This was his chance to brush critics aside and strike a confident note. Instead he left a sour taste.

The best leaders do not take umbrage. Imagine Kenneth Clarke interviewed hard on the heels of critical voices from his own side. Would he mope? Would he grizzle? Not at all. After a merrily noisy whinny at the preposterous miseryguts to whom the poor listener had just been subjected ('My goodness, James, where did you dredge that lot up?') he would have tipped a barrel of optimism over our heads and departed, chuckling.

Later, his party officials would have submitted a detailed complaint. 'My people have their jobs to do.' he would have laughed. 'And quite right, too. As for me personally — water off a duck's back.'

It isn't, of course, but you have to pretend. To a quiet man we might have warmed. But not to a grumpy man.

Matthew Parris is a political columnist of the Times