Despite a cold, gusty wind blowing drizzle into the packed crowd's faces, an increasingly loud, increasingly passionate chorus of "Come on you boys in brown!" rings out from thousands of throats. Even the forces of nature seem powerless against the all-encompassing, goose bump-inducing fan-made spectacle. The 17,800 sell-out crowd at the Millerntor ground, the vast majority supporting home side FC St Pauli, served up a trademark show of unity, support and identification with their heroes last Friday evening.

The scene was slightly surreal given what had happened just seconds earlier. Axel Bellinghausen, a 24-year-old midfielder for 1. FC Kaiserslautern, a proud club fallen on hard times in the German second division, had just netted with a deflected long-range drive right in front of the vociferous home support to seal a 4-3 away victory. Against the damp, black sky over the Hamburg pleasure district of St. Pauli, the late strike should surely have silenced even the most hopeless optimists among the promoted home team's diehard supporters, but that would be to misread the mood at the heart of the city of a million-and-a-half. Silence is alien at a club which has so often come close to extinction only to haul itself back from the brink, and especially so at a Friday evening match in early December, with light blazing down from the old-fashioned floodlight pylons, contrasting starkly with the colourful illuminations emanating from the thrice-yearly Dom funfair just a few metres away.

St. Pauli oozes football, and a lot more besides. The party never stops here, especially along the (in)famous neighbouring Reeperbahn, where the predominantly red lighting has made the district a magnet for visitors from all over the world. There's no such thing as closing time here, but the fans who have managed a few hours' sleep will wake up without the slightest regret at three more points dropped, even if they could ultimately prove fatal in the battle against relegation. The priority is unity and comradeship, more important even than the men in brown's success on the green sward. And curiously enough, the colour green is also highly significant in these parts. On Saturday lunchtime, the fans turn their attention to Scottish football, with one question on everyone's lips: 'How are Celtic getting on against Hearts?'

The friendship between fans of the Glasgow giants and these self-proclaimed outsiders from the Hamburg district of just 27,000 souls must rate as one of the most unlikely in the world game. At first glance, the 41-time Scottish champions have absolutely nothing in common with the club whose greatest sporting boast is to have led the Bundesliga once, after the opening day of the 1995-6 season, and who even now fondly style themselves 'Conquerors of the World Club Cup winners', due to a solitary home victory over Bayern Munich in 2002: bottom club St. Pauli won 2-1 in the Bundesliga shortly after the Bavarians had returned home from Tokyo with the trophy. However, as 41-year-old Sven Brux, responsible for event organisation at St. Pauli, revealed to "Our friendship with Celtic is essentially social."

'Stunned by the Celtic fans'

Brux is a perfect reflection of St. Pauli itself: open, lively, cosmopolitan and thoroughly unconcerned with image. He was the first St. Pauli representative to travel to Scotland, back in the early 1990s. And he was also one of the first to maintain regular contact with Celtic, journeying to Glasgow and around the continent for big European nights. "A couple of us were there again on Tuesday for the match against AC Milan," the towering 'St. Paulianer' relates, coming over less as an official and more as a diehard fan - perhaps typically for the club.

The first friendly meeting back in 1995 ended appropriately in a draw, since when groups of fans have regularly exchanged visits. The burgeoning relationship is fuelled by the similarity in the fans' attitude and philosophy. Both sets of supporters profess undying and unwavering loyalty, through the lean as well as the fat times. And both sets of fans provide an exemplary model of backing a team to the hilt without resorting to violence, recrimination, and a lack of respect for opponents.

"When I first saw Celtic play in Cologne, I was stunned by the friendly and exuberant atmosphere created by the supporters," says Pauli fan liaison officer Heiko Schlesselmann. "Normally, your true fan is only interested in his team winning. But the Celtic fans just wanted their team to do its best. They were proud of the players for giving everything for the cause, even if they lost, and never once booed their opponents." In short, the clubs are bound together by a shared ideology emphasising fraternity and communality over individualism.

The understanding between the fans from Hamburg and Glasgow is entirely mutual. St. Pauli memorabilia in brown or black are a regular sight in the stands at Celtic Park - indeed, the Bhoys' official club superstores even stock a St Pauli range. The Millerntor terraces, meanwhile, are speckled with green and white. There is a great deal more to this than sport. It is a demonstration of the game's power to unite people and their ideals, bringing them peacefully together. "And it goes without saying that both sets of fans know exactly how to party," concludes a grinning Brux.