Four in the morning in San Antonio's West End and the wildlife comes out to play. Beer bottles smash on to the pavement but the human swarm hears nothing over the music pounding from bars.

The doors of the Nightlife disco open and two young men barrel past the bouncers, vomit smeared on their bare chests. They embrace, then wrestle, then soil each other's hair.

Five teenage girls watch and applaud until one is grabbed by a bouncer and carried on his shoulders up the steps. One of her friends lunges to try and pull down the exposed knickers. The bouncer whirls and his captive's knee-high white boots catch the lunger in the face. She howls.

At the bottom of the street four lads sing: "No surrender to the IRA" while their friend shakes a sapling. It refuses to crack so he kicks it and urinates instead.

Round the corner the 24-hour first-aid station gets another arrival: a 17-year-old Lancastrian with a bloodied face and shirt and panic in his eyes. It is the first time he has been beaten up.

Two olive-uniformed Guardia Civil policemen sit in their squad car and stare straight ahead, expressionless. A drunk is leaning in their window demanding directions to the "cathouse". He says he's also a policeman and entitled to a discount.

Dennis Mackessy (27) looks around nervously and makes a confession. "I've been all round the world and I've never been afraid to tell people I'm Irish. But this lot are unbelievable, I can't open my gob." Three skinheads swagger towards Fernando Dominguez (18) a tiny kitchen porter from Capone's Chippy. He sees them, drops his bag of rubbish and scuttles into a doorway.

This was Monday morning, just another day in what passes for routine in San Antonio, a seaside town in the north-west of Ibiza. A maelstrom was enveloping the revellers, but they were too drunk to know or care. The local paper, Diario Ibiza, had branded them animals, and pushed Michael Birkett over the edge: Britain's official representative on the island had quit in disgust at his countrymen's depravity. His resignation became official this week, unleashing a torrent of media abuse against the revellers.

They had turned a paradise into the Gomorrah of the Med and dragged Britain's reputation through the mud. Diplomacy evaporated from Birkett (51), a vice-consul paid to look after them. They were degenerates, out of control, he fumed. Birkett's prescription, at least as reported by a Sunday tabloid, was a measure of his ire: the miscreants, he suggested, should be gassed.

Looking out at the passing hordes, the receptionist at the Piscis Park Hotel spoke so softly it was difficult to hear. "I hate them, I really hate them. The English behave like pigs, they respect nothing, they know nothing." The hotel's guests, like the rest of the town, were 80 per cent British.

The receptionist's eyes followed a guest leading in her catch, a good-looking boy in trainers and jeans. "You think they care that I hate them? They don't care." He was wrong. The couple, it turned out, did care. "There's a real community here," Denise explained later. "I've been coming here for five years now and these people are like my family. To make us out to be some form of ravers - I hate that word - is just so unfair. Our parents read that word and think horrible things about us but in fact we're just here to have a good time."

To understand the apparent contradiction between the receptionist's contempt and the apparent sensitivity of British visitors like Denise, you need to understand that there are two Ibizas. Turn right out of the hotel and a two minute walk takes you to the West End, a strip of a few dozen bars teeming with the over-dressed grist of the package holiday mill. But turn left out of the hotel and you reach another Ibiza, mellower and populated only by the more stylish and athletic of the island's visitors.

Here British people don't drink until they vomit, don't fight and squawk and try to pull down knickers. The fact that they appear to be the vast majority is even more surprising. Look deeper and something else emerges. Even those in the West End aren't widely despised after all. Ibiza's natives have not turned against them.

Behind the puke and sweat they see a more complex picture in which the louts are ordinary kids manipulated by a voracious industry.

William Crichton (38) knows something about it. Half Spanish and half Californian, he owns Bar M, a two-minute moped ride from the West End. "Most of those who come are clubbers. That means they don't drink too much, maybe a little Red Bull and vodka. They're aesthetes, they care how they look.

"The clubbers have revived the spirit of the artists who settled here in the '50s. That ethos died in the '80s, until club culture arrived. It's a mass movement and Ibiza has become its world centre. The energy it brings is something very positive."

There were people who came to get drunk and fall over but they did that everywhere. "It depresses me that the media have always picked up on the West End and applied it to the whole island. Is all of Britain like Newcastle on a Saturday night?"

The theory of clubbers' good behaviour wobbles at the entrance to the SES Paradis nightclub. A boy is pushing a girl's T-shirt over her breasts and his tongue begins to flick. She turns around to squirm in his lap and seconds later he appears to relax. Inside the vast cavernous interior, the decor is all mock Graeco-Roman and naked bodies gyrate on TV screens. Orgiastic hedonism could scarcely find better quarters, yet the hundreds of toned bodies do nothing more than dance. Few dance with, let alone touch, each other.

Shouting above the music Danny Drew (21) from Sussex, says no one is drunk. "It's too expensive, but that's not why we're here anyway. You just bring your bottle of water and refill it."

It was impossible to gauge how many of the ecstatic dancers were fuelled by the tablets on sale outside. Few males bothered to stare for long at the girl in spangly red hotpants and boob tube gyrating on the platform: they were concentrating on their own moves.

One girl nodded sadly when told of Birkett's resignation. "That's thanks to those fat fools in the West End. Check them out and you'll see what I mean."

Which takes us back to the bare-chested young men gleaming with vomit outside the Nightlife nightclub. A gruesome spectacle, for sure, but look closer. Andreas (38) the Spanish bouncer, is checking that they're OK. Satisfied they are only larking, he returns to the door and excuses their behaviour. "They get sick, so what? As long as they're not violent it's OK. We need these people, without them we've no work. What then?"

Further up the street Dominguez, the skinny kitchen porter, says he's cowering in the doorway not to evade skinheads but because he's spotted an ex-girlfriend.

At the first-aid station Dr Basil Safar, the head of San Antonio's accident and emergency unit, says his beaten-up Lancastrian patient is highly unusual. Traffic accidents, food poisoning and pensioners' frailty provide his regular workload.

He scoffs at media reports that 50 Britons die on Ibiza each year: "No way. One a month maybe, usually a heart attack or moped crash." He is mellow about the drinking. "When I was 17 I had my stomach pumped. I was stupid, we're all stupid at this age. Anyway we only do about one stomach pump a fortnight." Safar can't understand the fuss over Birkett. "It's just kids."

Mackessy, the nervous Irishman, has another confession. "The English aren't as bad as they're painted. Hundreds of them watched the Liverpool-Newcastle match in the pub and there wasn't a glass raised in anger." Even the passed-out drunks were partly exculpated by Antoni Mari Tur, the mayor of San Antonio.

"They are kids away from home going crazy, but the ones I blame are the tour operators. They used to take commission only from the hotels, now they take it from bars and discos."

Vouchers, flyers, excursions and discounts were being used to push them into bars and keep them there with the collusion of bar owners. Clubbers at Ibiza airport complained they had been ripped off by operators' representatives. The mayor said he was mystified by the publicity.

He suggested Birkett was temperamentally unsuited to a job involving young people. "It's better now than five years ago. Young British people are normal."

A point echoed by Cristina Amanda Tur, the Diario Ibiza reporter whose "animals" comparison was cited in the news-papers as a sweeping condemnation. "I only meant a tiny minority, not the ordinary English. I don't know why the press got so excited."

Among the clubbers, the curious affair of Britain's Man in Ibiza was debated with wry nonchalance. No one was surprised by his outburst, they said. Ibiza had a knack of inducing excess.