For the truth about kinky sex practices, look in the mirror

What a funny business other people's sex lives are. Our own are, of course, pretty ordinary. They consist of fumbles, grunts, yearnings, transient passions, strangely enduring affections, awkward logistics and meal breaks. Does she want to? Is he too tired? Where shall we meet? Will the kids go to sleep before all lust has finally fled? Wouldn't it anyway be simpler - in all circumstances - to stay in and watch telly?

But - as measured by the sales of tabloid newspapers, and as recounted in their tales of broken marriages - the lives of celebrities, MPs, footballers and vicars are far richer and more urgent than ours. They cheat, rage, engage in all-night bouts of kinky lovemaking and dress up in odd clothes. Sex for them is very different from what it is for us. Apparently.

In the case of Conservative MP Piers Merchant and his "friend" Anna Cox , their sex life is so remarkable - so phenomenal - that it has justified half a dozen reporters and several photographers from the Sunday Mirror (a stepsister paper of this one) tailing them across northern England, taking snaps, talking to hoteliers, checking invoices and eavesdropping on their conversations. It is quite possible that these intrepid seekers after truth have even discovered positions and dimensions, but are content (for the time being) to keep those details to themselves.

Now, adultery clearly shocks our colleagues. From their descriptions of Mr Merchant's behaviour it becomes possible to imagine the sense of disappointment and genuine anger which attended the early editorial conferences at which the revelations were discussed. Many tabloid journalists are devout Christians, who would rather throw themselves from the top floor of Canary Wharf than sleep with young trollops, or stay out late drinking when they could be in the bosoms of their families helping Joshua and Natalie with their homework.

Even allowing for this squeamishness, however, the descriptions of the Merchant Affair suggest something very unusual. The 12.50 from York to Newcastle, for instance, may be an ordinary diesel to you and me, with smutted windows and a loo seat that falls with an almighty bang - but to those writing about Piers and Anna it is the Love Train, its onward rush into the tunnels of North Yorkshire invested with blind, phallic vigour.

One moment Anna, "her blonde hair falling on to a tight-fitting dress which perfectly displayed her new 36DD breast implants" jumps up, "squealing with delight". And the next she is cooking a "barely edible meal of pasta in tomato ketchup on a bed of lettuce". Anna gives Piers a "smouldering look", but worries that his gift of Milk Tray will make her fat. "At Pepe's fast food bar they ordered kebab and chips," then "Merchant sat looking intently into his young lover's unlined face". The fabulous alternates with the mundane to create a picture that is at once familiar and alien.

Now, I have not slept with many 17-year-olds recently. Not since I was 18, in fact. But I cannot help wondering whether aspects of my life or, dear reader, of yours, might not look similarly weird were we to be followed and bugged and photographed and written about by the born-again Christians of Canary Wharf. How might the masturbators amongst us feel were our solitary acts to be described in tabloid circumlocution on page 1 of the Sunday Mirror, our faces snapped in post-climax astonishment? What about the e-mail adulterers, caught out flirting electronically? Or the tipsy chat-up artist trying it on unsuccessfully with the office beauty for the umpteenth pathetic time? Could we not find ourselves likewise the objects of ridicule - would-be cheats and sexual failures? Or just dullards?

Maybe I'm being too optimistic, but I have a suspicion that more of us now realise what kind of a game is being played here. If we dress up our natural prurience by suggesting that there is something remarkable - and simple - about the Merchant adventure, or the breakup of the Hoddles' marriage, or Bill Clinton's li'l ol' man, then we can somehow justify sending poor, easily shocked journalists out to write stories about it.

But increasingly the wind is tugging at the figleaf. The Hoddles, for example, are exactly like us. Forty per cent of our marriages end in divorce too - and to us the reasons are both terribly complex and terribly ordinary. Why should we seek the reason for the separation? And how would we know it were we to discover it, when we often cannot explain ourselves to ourselves? Likewise the vanities, timidities and sadnesses that combine to govern our affairs may be presumed to govern those of others. They are no different.

So, do you have a right to know about the love lives of MPs, the marital condition of soccer managers or the penises of presidents? Only, I would suggest, if they also have the right to know about yours.

I would only make one exception to this rule. On Newsnight on Tuesday or Wednesday the Tory MP, Gerald Howarth asked Jeremy Paxman and Bridget Rowe (Sunday Mirror editor) if they had never had affairs. Paxman - rightly - did not reply. Rowe - equally rightly - did reply. She is the exception. Tabloid editors should answer.