Last Wednesday night, during a BBC2 drama about sixteenth-century witch-hunts, BBC airwaves played host for the very first time to what I believe the more delicate members of society refer to as 'the c-word'.

When I read Tuesday's papers and learned what was due for broadcast the following night, I was deeply shocked. Horrified, in fact. I could barely believe what I was reading. Nobody had ever said 'cunt' on the BBC before? Incredible! I assumed they'd been saying it for years. It was like reading the reports of Eugène Ionesco's death in 1994 - all you could think was: 'Ionesco was still alive ?'

We have settled into a rather strange relationship with swearing. We expect to hear it on TV after nine o'clock at night, but phone to complain if we hear it in the daytime. We don't mind it in gritty dramas about domestic abuse, but we find it gratuitous in comedy. Away from television, we'll happily say 'fuck' in a pub but not in church. We turn all matey and familiar if a builder swears, but would be horrified to hear the same language from a policeman. Even a student friend of mine who insists: 'Swearing is never inappropriate!' adds thoughtfully, 'except perhaps during the marriage vows.'

It doesn't add up. Surely these words are either rude or they're not? We've either moved on or we haven't. In 1914, when Mrs Patrick Campbell shouted: 'Not bloody likely!' on stage in Pygmalion, the tabloids announced their outrage at 'a word which the Daily Sketch cannot possibly print, and is certainly not used in decent society'.

We smile at that preposterous innocence now, but nodded sagely over the tabloids of 2002 when they raged about Ali G saying 'motherfucker' on Radio 1. The certain knowledge that 90 years from now our own great-grandchildren will be saying: 'How sweet, they actually used to think that "motherfucker" was rude!' seemed to make no difference at all.

Some people believe that it's all about when kiddies might be listening. Ali G was condemned because he used that word on breakfast radio 'during the school run'. And how precisely do people imagine conversation in the school playground? 'Good morning Cyril; I eagerly anticipate our football game this afternoon and I trust you feel the same'? I suspect the kids are already pretty familiar with swearing. In fact, they're far more comfortable with it than adults are.

Similarly, Caprice (the model) declaimed the word 'cunt' merrily every night on stage in The Vagina Monologues but got into terrible hot water when she used the same word on ITV1's This Morning. Pre-watershed, you see. But don't tell me the kids would be offended to hear slang on This Morning - they'd have greater objections to the gardening segment. Small ears are a red herring (if that's not too peculiar an image) because grown-ups have all sorts of separate rules about when they themselves can tolerate sailor talk. A survey issued in 2000 by the BBC, ASA, BSC and ITC found that three-quarters of responding viewers had no problem with expletives uttered 'in shock', but didn't like them used as a matter of routine. So: fine when you stub your toe, but not good when you ask someone to 'pass the fucking salt'.

Of course, we can all sympathise with a loud toe-stubbing curse. The word 'cunt', often mistakenly called 'good old Anglo-Saxon language', is in fact related to Old Norse - you can quite understand why those poor ancient Scandinavians (stuck in pitch darkness for six months of the year) would come up with a fair few swear words. If nothing else, they must have been constantly banging their knees on things.

Nevertheless, if I had taken part in that survey I would have argued the precise opposite. Casual, 'routine' expletives don't bother me, but I don't like angry or violent swearing because I don't like anger or violence. There's no point having rules about language, because location, audience and hour of day are utterly irrelevant - the key thing is the sentiment expressed. And you can express foul sentiment in any words at all.

During the Oz trial in 1971, George Melly told the court that 'liberated' people swear happily all the time. The horrified prosecutor asked: 'Would you call your 10-year-old daughter a little cunt?'

And Melly gave what is surely the only right answer: 'No, because I don't think she is.'

Speaking of answers, they say a politician can never give a straight one. Just in case, I tuned in to hear Iain Duncan Smith discussing immigration on Radio 2 last Tuesday.

During the opening chat, Jeremy Vine asked the Opposition leader if he liked the music of Fatboy Slim.

'Well... he's OK,' said Duncan Smith. 'It's yes and no really.'

I decided not to stick around for the asylum discussion.