It is almost as if St Pauli lies dormant during the day, absorbing the sun’s energy. At night it explodes into supercharged life. As well as the sex trade and musical shows, it has one of the most vibrant club scenes in Europe with venues like The Academy, PAT, Location One and Cult attracting clubbers from all over the city and beyond. Even on a Tuesday night, one of the least pleasure-focused days in the north-German psyche, the party goes on until dawn.

MacSwain parked in the Spielbudenplatz Parkhaus. Paul dropped Anna at the entrance to watch for MacSwain coming out and parked further down the street. He then took up a position opposite the entrance, in front of Schmidt’s Tivoli. MacSwain emerged from the Parkhaus. He was dressed casually but expensively and moved with a relaxed assurance. He didn’t notice Anna, who turned away and crossed the road before making a U-turn to follow on behind. In the meantime, Paul had picked up MacSwain and was walking about three metres behind him, but on the opposite side of the road.

MacSwain led them out of Spielbudenplatz, diagonally crossed Davidstrasse in front of the Davidwache police station and into Friedrichstrasse. Anna caught up with Paul and linked her arm through his, a simple gesture of intimacy that instantly transformed them into a couple. They passed the Albers-Eck, with its landmark corner doorway. Somewhere, one of the pubs was having a Schlager night, and the enthusiastic blandness of German middle-of-the-road music spilled out into the street. MacSwain crossed Hans-Albers-Platz and walked into a dance club, receiving a nod of acknowledgement from one of two doormen who looked as if between them they kept the German steroid industry in business.

‘Shit,’ said Anna. ‘What do you reckon?’

Paul drew air in through his teeth. ‘Don’t know … it’s going to be heaving in there. If we go in he could come out before we even lay eyes on him. And if we hang around out here, we’re going to stick out like a sore thumb.’ He quickly surveyed the square. ‘We could get some back-up to park themselves out here, but we’re exposed while we wait … Let’s go in and see if we can find him. If we can’t, we meet back at the door in fifteen minutes. Okay?’

Anna nodded her assent. She led the way up the steps to the nightclub. One of the huge doormen looked at Anna’s leather jacket and laughed derisively. As she passed him he placed a restraining hand on her left shoulder. Anna’s right hand shot diagonally across her body and grabbed the bouncer’s beefy thumb. The doorman tilted sideways, singing an ‘ahhhh’ song as he stared at his thumb, amazed that it could bend that far.

‘No touchie!’ said Anna sweetly.

The other hulk moved forward. Paul stepped in his way, holding his Kriminalpolizei shield in the doorman’s face. The heavy stepped back and swung the door open for Anna to enter. She let the doorman’s thumb go and he cradled it in his other hand.