To be honest, I've just about had enough of celebrities and their charity antics these past couple of weeks. I don't want to read another column about Madonna and her adoption saga. I don't want to see any more pictures of stars touring refugee camps or orphanages.

Why? Because it seems that, more often that not, it's the celebrities who become the story rather than those meant to benefit from their glitzy presence.

So I couldn't help but chuckle with pleasure at Sue Ryan's article in this week's Media Guardian, which exposes the crazy world of working with certain U.N. goodwill ambassadors.

Ryan - a former managing editor of the Daily Telegraph and honorary fellow of UNICEF who was supposed to be travelling with U.N. children's fund ambassador Jemima Khan to earthquake-affected areas in Pakistan this autumn - was unceremoniously booted off the trip at the last minute. Instead she decided to write about the machinations in the lead-up to the disaster extravaganza.

The plotline of who was meant to be going with who, the many changes and finally who wasn't allowed to go is way more complicated than your average soap opera. But, as described by Ryan, it makes for quite a farce.

Ryan's key point is that what should have been coverage about earthquake survivors and UNICEF's work to rehabilitate their lives was dominated by Jemima's role as a UNICEF ambassador and even turned into a kind of fashion shoot (ES magazine photographed her in a succession of expensive designer clothes). This despite the fact that Jemima was quoted in the magazine as saying she didn't want the trip to be "a pointless PR exercise or photo opportunity".

By pandering to the demands of Jemima and actress Trudie Styler, who also came along, UNICEF effectively lost control of the trip and also of the coverage, Ryan says. "UNICEF, so strong and brave in the field, had been wimps when faced with the force of celebrity," she writes bluntly.

Aid agencies should take note. Celebrities aren't a one-way ticket to positive media coverage. They may help grab some attention, but what kind? Using them unwisely can backfire badly, as this cautionary tale shows.

One consequence of the growing celebrity/charity entanglement may be that the public becomes more sceptical of media coverage pegged to fame and fortune.

As Ryan argues, "Celebrity and charity have long been bedfellows but never more so; the increasingly relevant and awkward question is whether they make a comfortable partnership."