If you're going to the ball, don't forget to take your balaclava

IT IS midnight. In the near distance, a May ball is in progress. Stealthily, two figures emerge from the undergrowth and stride towards the light and noise. As if from nowhere a burly form rises to meet them. 'Can I see your tags please, gentlemen?' Minutes later, to a shout of 'Don't let me see you again]', the two are ejected from the college's front gate. The ball-crashing season has begun in earnest.

Damon, a third-year Cambridge law student, is awaiting the results of his finals. But tonight his mind is on other things. The pockets of his dinner jacket bulge with unlikely equipment: a torch, a balaclava, tracksuit trousers. He brandishes scissors, tape and a tube of superglue. 'These are the most important,' he explains. 'If you can get a security tag off someone, you're half-way there.'

The practice of gatecrashing May balls is as old as the balls themselves. Damon is not alone in his endeavours. The bushes outside colleges rustle with unseen bodies. Tonight, he and other gatecrashers are spoilt for choice. Cambridge is hosting nine major balls this year, and three of them, Clare, Trinity and Downing, are currently in progress. Damon is hoping to 'do' all three.

Most students will admit to the occasional attempt at gatecrashing. But every year a hard core plans its efforts with almost militaristic fervour. Jonathan, a classics student, studies maps of colleges in order to work out his strategy - though he admits he could easily have met the price of the ticket. 'It's just this buzz you get,' he says. 'It's a bit like mountain climbing. You do it because it's there.'

Among gatecrashing veterans, some favour the 'Errol Flynn' approach, scaling walls and drainpipes. Others say that security has become so tight that the only way in is to bluff it.

University folklore is shot through with tales of outrageous gatecrashing attempts. One year, two students supposedly arrived waving forged press cards and were toasted all night by the ball committee. On another, a student 'borrowed' two punt poles and persuaded security that he was a stilt- walking act. Members of the university potholing club claim to have gatecrashed Trinity en masse by way of the town sewers. Recent, more verifiable attempts have not met with success.

One female student recalls how, when confronted, her boyfriend bolted and left her swinging in her balldress from a drainpipe.

This year the stakes are higher than ever. Recession and student poverty have resulted in falling ticket sales, and several Cambridge balls were cancelled. The others are spending increasing sums on professional security firms.

Some students regret the loss of sporting spirit. 'It's just too difficult now,' says one failed gatecrasher. 'Even if you get in, they check you for tags every five minutes.'

But this year's balls have already yielded a host of anecdotes. One enterprising student tried to swim into Magdalene with a wet suit over his evening clothes. Security guards threw him back in to the river - minus his scuba gear.

Damon, meanwhile, is happy with his efforts. He managed three balls, although Clare eluded him. Will he try again? 'I think I've had enough now. You eventually get tired of this sort of thing,' he says. 'Now doing security - that would be a laugh .'