The Hamburg derby is a clash of cultures. On the west of the city sit Hamburger SV, one of the most storied, important and recognised clubs in German football. Their nickname, Der Dino, suggests how long in the tooth they are. In their illustrious history, HSV have won six Bundesliga titles, three German Cups, one European Cup and one Cup Winners’ Cup. Simply put, they are giants of German football.

HSV’s place in the Bundesliga was so permanent that they installed a clock in their ground to show off how long they had been in the top flight – down to the last second. That clock has now stopped. Having been ever-present in the Bundesliga since its inception in 1963, the club were finally relegated to the second division this year.

And that’s where St Pauli join the story. Hamburg’s second club are probably more famous for their philosophy than their football. They sell more merchandise than their city rivals – and most sides in the Bundesliga – even though they have only featured in the top division for eight seasons and have never qualified for a European competition. Their punk tradition and opposition to racism, fascism, homophobia and sexism have made them a global symbol of the political left. But their football has not always kept pace with their popularity.

When St Pauli finally made it to the top flight in 1977 and beat their city rivals in the derby, some HSV fans applauded the brown and whites, not seeing this otherwise regional club as a major threat to their dominance. In many ways they were right. St Pauli finished bottom of the league that season and would not beat HSV in the league for another 34 years. The last time they played in the top flight, in 2010-11, they finished bottom with just eight wins from 34 games.

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These two teams rarely have the chance to play each other – they had not met for seven years before this season – so HSV’s relegation and the return of the derby has been big news in Hamburg. It has also opened up old wounds and prompted new debates. Are St Pauli as pious and politically pure as they think? Are HSV fans jealous of their rivals and guilty of goading them? We wanted to find out. So, when a sellout crowd of 57,000 fans packed into the Volksparkstadion to watch the sides resume hostilities a few weeks ago, we joined them to experience a derby that has reached a crossroads.