And this week's unlucky loser? Well, it can only be the host

"Welcome to the show", said Angus Deayton, "this week's loser is ... presenting it". It's known that participants in Have I Got News For You spend hours polishing their off-the-cuff witticisms, but in the circumstances this wasn't bad. Celebrity philanderers know that discovery leads to tabloid humiliation; some might even expect extra mortification from the BBC's long-running news quiz. But few have had to force down quite such a large slice of humble pie as the show's own presenter, a dandified scourge who knew that now he was to be principal whipping boy.

If he'd imagined that a bit of self-administered punishment would make the others go easy, though, he'd got it badly wrong. Just two minutes in, Ian Hislop and Paul Merton were flaying him and it was hopeless even attempting to divert them. Backed by copies of the News of the World that broke the story of Deayton's dalliance and drug-taking, they pinned him down in turns. "The story I'm really interested in Angus ... how did you manage to avoid paying her?" Deayton tried to keep pace – or at least his autocue did: "There is no need to adjust your set," he said, "my face is this red".

But after a while his own references fell away to be replaced by a look of queasy stoicism. Viewers who had ever wondered what a "shit-eating grin" actually looks like had their curiosity satisfied, as Deayton was force-fed the mess he'd left behind him in a Hilton hotel room.

The only thing that distracted Paul Merton was a story on featherless chickens – the kind of surreal oddity that would usually fuel some wild improvisation. Losing his concentration momentarily, like a Rottweiler distracted by a toy, he unclamped his teeth from Deayton's leg, to sniff at this alternative comic possibility. But it didn't divert him for long. When Deayton made the mistake of a remark that sounded self-justifying, hinting that the story had been inaccurate in some respects, Merton pounced: "Which bits aren't true then?" he asked, knowing it was an unanswerable question. By the end of the programme insinuation had been reduced to monosyllables – all Merton had to do was add "Do you?" or "Really?" to anything the presenter said and the English language's rich fund of double entendre did the rest.

Deayton didn't look as if he was enjoying this – and who could blame him. But whatever the motives of his colleagues he should be grateful. This was teasing, if merciless, and the implication of teasing is that its object is relatively harmless. Every joke amplified the sense that Deayton had got himself into the sort of scrape that can happen to anyone – an embarrassing pratfall rather than an emotional betrayal and an, allegedly, criminal act. They might have put him on a hook but they also got him off it.