Janet Street-Porter: Nice work if you can get a grant to pay for it

Once you enter the rarefied world of academia you are entitled to examine Kate Moss and her success

Organised by the University of Paisley, more than 80 delegates from across the world have pitched up to read densely argued papers on such taxing issues as "Age and Sexuality in Celebrity Culture - the case of Helen Mirren" and "From Disney to Dirty: Christine Aguilera and the Representation of Gendered Ethnicity".

The three-day agenda could have been written by any 12-year-old with an interest in reality television, gossip magazines and the soaps. The only difference is that we make school children read Dickens and Philip Pullman, whereas once you enter the rarefied world of academia you're entitled to examine Kate Moss and her success promoting everything from Rimmel to St Laurent, and come to the entirely predictable conclusion that Elizabeth Hurley has prolonged her career by moving from modelling into other fields, such as fashion design, all in the name of research for your degree or doctorate. Yesterday, one delegate actually had the nerve to produce something entitled "Reading Heat Magazine", while a whole session was dedicated to the dissection of David Beckham by three different boffins.

Of course, David Beckham is a fabulous person to write learned theses about, because we know that his wife doesn't bother reading books, he doesn't bother speaking more than is absolutely necessary, and both of them are like a super duper celebrity cruet set we can't seem to do without a daily fix of.

Carlton Brick from the University of Paisley devoted a lot of energy to proving that Mr Beckham's life is littered with Christian symbolism. From calling his son Cruz to adopting a Christ-like persona in photographs (as in the Sam Taylor- Wood video portrait), David is, apparently, a "Post-Modern religious icon". Using two of the most hackneyed words in popular culture - icon and Post-Modern - only shows you just how shallow you can pitch yourself if you cleverly wear the coat of scholarship. Mick Jardine of the University of Winchester decided that Beckham was a modern version of the Arthurian legend, just another knight in shining armour.

Once you have been deemed to be worthy of a pap shot, then somewhere a professor is starting to put together a thesis on your dentistry, underarm hair or song titles. Madonna is the Queen of media control, and put in an appearance at her husband's movie premiere this week bravely sporting her arm in a sling. But even she could not prevent the entire event degenerating into a morass of critical sneering, when the film turned out to be a clunker.

If you've married a man who couldn't direct traffic, all the lipstick and Prada tailoring going isn't going to divert attention from the fact that his career is in the doldrums, while yours, after a judicious appearance on Live8, is still going strong.

The University of Paisley has been running a course on celebrity culture for some years, and it's clear from the delegate list at the conference that this rich subject is now the focus of frenzied research in academic institutions from Michigan to New York to Aberdeen to Alberta to Finland.

Nice work if you can get a grant to pay for it! I'm not denying that we are living through times when famous names dominate the media and advertising. But really, what's changed? In Christopher Marlowe's time rumours and speculation about prominent figures were debated in pamphlets eagerly lapped up by Londoners every week.

Now we have global media and an ease of communication so that gossip and trivia can be endlessly spun to fill the space available. Displaying an interest in celebrity is nothing new, or shameful about our society. It's really a spectator sport and even reading the ghastly memoirs of Max Clifford in the Daily Express this week will be brightening some people's day.

But what is new, and worth considering, is how many "celebrities" now feel it is their duty to engage in moral issues. It's almost as if they feel guilty for earning plenty of money for being good at what they do for a living. In return for us paying dues to watch them at the movies or play their latest record, they feel compelled to preach to us for free about poverty, child abuse, cancer and world debt.

As I have said before, there's not one reader of this paper who doesn't have a core commitment to wanting the injustices of this world righted, but do we need to be reminded about them by Annie Lennox, Sir Bob or Colin Firth? Take the beautifully glamorous Make Poverty History adverts featuring a range of personalities clicking their finger to remind us that a child dies every three seconds through preventable causes. Even though they were aired around the world, and on television channels in the UK last Christmas and in March, Ofcom has now ruled they contain a political message and should be banned. In my opinion they were completely unnecessary anyway.

Now Sir Bob has come in for criticism as some in the charity lobby break ranks and accuse him of over-playing the achievements of Live8 and the G8 summit at Gleneagles. No one can deny his huge personal effort to try to make the world a fairer place, but at the heart of his endeavours lies a misunderstanding of how politics works.

A gorgeous, star-studded event attended by lorry loads of celebs filled newspapers with photos and created a huge television spectacle. But the intertwining of fame and charity will ultimately end in tears. Every event will be committed to raising more than the last, and the small, unsung organisations all over Britain who raise money in church collections and at fetes and jumble sales for clean water for Africa and food for refugees year in and year our will all be ignored as advertising agencies and record companies carve up the next big media event involving actors, models and musicians.

It's a brilliant way to rebrand stars and sell product, all in a good cause. Meanwhile, politicians conveniently forget or fiddle what they signed up to when the cameras were rolling.

Perhaps the 500 charities which came together in the coalition to Make Poverty History could take a deep breath and realise that they have to streamline how they operate, and they don't need big names to put their message across. We all have the power to cancel national debts, stop children dying and end restrictive trade agreements.

It won't be done by wearing a bit of white rubber around your wrist but by how you vote at the ballot box. That sends a more powerful message than any charidee record or gorgeously shot ad campaign.