There was, however, no easy vantage point from which to keep an eye on the barge. This wasn’t the sort of place where people went for an evening out to sit around watching the water traffic. It was a working harbour where men went about their business. The only advantage he had was that it was already almost dark. In half an hour or so, nobody would notice him standing in the shadows of the low brick building at the landward end of the wharf. He tried to look like a man who is waiting to meet someone, pacing to and fro and looking at his watch.

Twenty minutes passed and the night gathered around him, broken by pools of harsh light from the lamps that illuminated the wharves and the softer hazes of brightness from the boats themselves. He was so intent on his surveillance that he didn’t notice Marijke’s arrival until she was right next to him. ‘I spoke to the team. They’ll be here in about twenty minutes. Anything happen?’ she asked.

‘No sign of life.’

‘So, now we wait till my people get here.’

‘We have to wait anyway. I need to get him alone.’

‘OK, but we should be ready for when the others arrive.’ Marijke fiddled with the radio equipment, clipping the pen to Tony’s jacket pocket and inserting her earphone. ‘Walk down the jetty and talk to me,’ she said, readying the minidisk recorder that completed the system.

He set off, nerves jangling, forcing himself to walk at the right speed. Too slow and he’d look incongruously like a tourist; too fast and he’d draw attention to himself. Already his mind was racing ahead to the encounter with Mann, and he tried to calm himself by focusing on his surroundings. The evening air had a cool bite to it, counteracting the heavy stink of diesel fumes and the odd whiff of cooking food that came from the barges moored alongside. But Tony felt hot and clammy, perspiration making his shirt cling with all the discomfort of a wetsuit on dry land.

He was halfway along the wharf when two figures appeared at the wheelhouse of the Wilhelmina Rosen. ‘Oh shit,’ he said softly. ‘Marijke, we have activity. Two men, can’t see if either of them is Mann.’ Heart racing, he carried on walking as the pair came down the gangplank and headed towards him. They drew closer and he could see that neither was his target. They passed him without so much as a curious glance and Tony muttered, ‘Negative. I think he’s on board alone now. I’m going to turn round. If you can hear me, step forward into the light and wave to me.’ He turned to face the direction he’d come from and saw Marijke emerge into a cone of light. She raised one hand and let it fall.