A friend who spends his life negotiating with the agents of glamour models explained to me the principles of “boobonomics”. Let's assume a pretty girl, who has been snapped in her bikini for a local newspaper, seeks a big-time career. Her agent phones a men's magazine and proposes for a given sum, say £3,000, that she pose in lingerie.

If she's a hit with the readers, her agent will then suggest that for a greater sum, say £5,000, she will pose topless, but with her nipples concealed by her cupped fingers (“hand bra”). Subsequently her fee will rise for each coy permutation: “hair bra” or “girl-on-girl bra” (two models face to face shielding each other's breasts). Eventually, once this dance of the seven thongs has been exhausted and readers are believed to be slavering with anticipation, the agent will propose that for a huge sum — say £50,000 — the girl will finally reveal all.

But the harshest principle of boobonomics is that after this shoot, the value of the girl's assets — which is what they are in a technical, business sense — collapses. From this point she will only receive £20K for full topless, a sum she only recently received for showing far less. Her product life cycle is reaching an end. Now, however, agents have a new strategy for reviving the brand, rather as when Kit Kat launched peanut or orange-flavoured variants. He proposes that his client have a breast enlargement: would the magazine be interested in the first pictures, you know, when the scars have healed? The going rate for new knockers will never match her initial “reveal”, but raises her value momentarily to, say, £35,000. Jordan, the Milton Friedman of boobonomics, has amassed a great fortune increasing her breast size by increments in three operations.

On the Today programme this week I heard the writer Natasha Walter and presenter Sarah Montague despair of the thousands of young women who send their topless photos to a lads' mag Assess My Breasts website to be rated out of ten by anonymous blokes. They were particularly incensed that the girls claimed to do this because they find it “liberating” and “empowering”. But these concepts have been leeched of noble feminist meaning. They are now mere buzzwords employed by young women to give a hand bra of respectability to their real intent, which is to ascertain their boobonomic worth.

By this I don't mean that all these girls wish to become glamour models, although many clearly do, since for some it is arguably no more soul-destroying — and certainly more lucrative — than toiling in a call centre. Yet even those among the feisty high-achieving gals who form a majority in our universities, and may well have loving, equitable relationships with decent boyfriends, still can't resist checking their boobonomic bank balances.

Of course the correlation between sexual allure and money is timeless. The principles of boobonomics — build up interest, don't put out too much too soon — are not dissimilar from The Rules, the American dating strategies designed to bag a husband, which in turn echo the fan-rustling courtships of earlier eras. It is just that the link between sex and money is more pronounced than ever before.

The trend towards obsessive female grooming, surgical enhancement and tarty clobber is to maximise your worth in the sexual stock exchange: whether the market you are trading in is porn stardom or marriage. When a man who slept with a beautiful friend of mine remarked with satisfaction “I would have paid for that”, he expected her to take it as a compliment.

What happens when the imbalance in boobonomic transactions is too great is essentially the story of the Manchester United Christmas party. Here we have young men earning sums they literally cannot spend: their desire to consume to the fullest extent of their wealth is only frustrated by their mortality. Even an England international can't drive more than a single £150,000 sports car at once, has only one body to dress in fine clothes, to tank up with cocaine or Cristal.

But with sex the possibilities are limitless. “Dogging”, “roasting”, cruising the streets propositioning random women for sex (often successfully) are not actual monetary exchanges, although the women who agree clearly feel a car-park knee-trembler with a terrace god is confirmation of their high boobonomic value. But Premier League footballers also frequent high-class prostitutes because they can buy not only bodies but discretion: the sum they regularly pay them exceeds what the women would receive for a kiss-and-tell. And, crucially, all this sexual excess is no longer policed by public shame.

Rio Ferdinand announced two weeks before the great debauch that the team would invite the 100 most beautiful girls in Manchester. One hundred women: what an epic droit de seigneur. Not including the wives and girlfriends who, when they learnt they were banned from the party, must have grimly surveyed their Barratt mansions, their Hermès handbag hangars, contemplated their five-carat Christmas spangles, and tried not to wonder what lay ahead in the Great John Street Hotel's 30 reserved suites and penthouse hot-tub.

Perhaps some of the girls believed they could cash in that night. The beauty queens, the Hollyoaks stars, the models hired by the dozen through agencies, maybe they really thought this was their opportunity to bag a millionaire player. Others, the goosepimpled girls, not just from Manchester but far beyond, still queuing in the street at 3am hoping to be admitted, knew they were merely buying a lottery ticket.

But to the footballers themselves, any woman who came to this party had already been purchased. Why else would they be there? They were a facility paid for with the £4,000-a- head players' whip-round, laid on like the free pink champagne bar. The women guests had their mobile phones confiscated, just as Rebecca Loos, arriving at a Spanish hotel for her coupling with David Beckham, was told by security guards — following some established protocol — to hand over her bag and shoes.

Guests at the party complained that Wayne Rooney hinted at wanting threesomes, that Irish defender John O'Shea lifted passing skirts, that one girl was dragged unwillingly by a drunken player from the dancefloor to the toilets, that they felt like “pieces of meat in a cattle market”. But in a world powered by crude boobonomics, where there is a grotesque elision between sex worker and “empowered” girl, rape — or something not unlike it — was waiting to happen that night.

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