A few years ago I arrived - a bit under the weather - at the Glastonbury Festival. My tickets had to be collected at a certain gate (say Gate A) but I fell off the train somewhere closer to Gate X, and Gate A looked like it was a few miles away. So I did what everyone else was doing: jumped over a security barrier that came up only to my waist and trundled happily down the hill to the stage.

When I went to collect my tickets next day, the hippy type at the proper gate didn't seem at all put out by the time-space conundrum that meant I was asking for my entrance ticket from inside the festival. That was a problem with Glastonbury then: so many people considered it a human right to get into festivals for free (as opposed to people who were too shattered to walk to the relevant gate) that it put a huge strain on the existing facilities.

T the next festival, the Glastonbury Wall was erected, and the Mean Fiddler Group was drafted in to tighten up security. Although the wall was hated by everyone (including festival founder Michael Eavis) it was seen as a necessary evil and it did succeed in ensuring that numbers were kept to a manageable level.

However a new threat was around the corner. Because of its popularity, Glastonbury became a magnet for ticket touts. For the past few years, people who can meet touts' excessive sell-on ticket prices have made up a substantial portion of the festival audience. You can guess who these people are because they usually arrive in an SUV that their au pair dutifully unloads while they loudly ask about the availability of cocaine.

This year's festival, which starts today and runs all weekend, is being watched not just by Irish music promoters but by those from around the world. The festival has introduced a photo-ID system to combat the touts. The idea is simple: earlier in the year you had to register with your photograph and if you are one of the 138,000 lucky enough to get a ticket you will have to present your photo ID to access the festival.

Over the past few weeks, though, tickets for this year's Glastonbury have been up for auction on eBay. Here's why: as anybody with an unlikely- looking passport photograph will tell you, a head and shoulders shot of someone can be easily passed off as being of someone else. Michael Eavis himself has said that he is "disappointed" by the quality of the photo tickets.

Here's where it gets a bit complicated. One eBay seller who is offering his "white, male, mid 20s" photo ticket for more than the retail price claims that he can't get time off work to go to the festival and obviously doesn't want to see the £150 he spent on his ticket go to waste. The festival's policy is that ticket holders can get a full refund if they can't, for whatever reason, attend the festival but that this must have been done before May 5th.

Our eBay seller goes on to claim that when he got on to the festival ticket office to explain that it was only after May 5th that he found out he couldn't make the festival, he was told to pass his ticket on and that it was "not likely that any white, male with that ticket would be refused entry".

There could be madness this weekend as photo IDs and faces are scanned for degrees of likeness. After all the lofty claims of the first "tout-free festival", there may be some very argumentative "but it is me in the photo" scenes at the entrance gate. If this weekend ends in tears for some festival goers, then so will the idea of the photo-ID festival.