She beckoned him closer, and as he leaned in to look at the potatoes, she spoke loudly in his ear, well above the volume of a whisper, her breath hot and flecked with spittle. ‘Go round the block into Elbe Strasse; there’s a stall there that sells soup. There’s always a long queue, which will fortunately keep you occupied. Come back here in forty minutes, you understand that? Not before then. When you return, I’ll take you to the back: Ulrich will be waiting there.’

‘And how long ago was that?’

‘Ten minutes ago. Two of my guys followed him into Moselstrasse, where he headed straight to a stall selling potatoes. They saw him talking to a woman there. One of the team thinks he heard her telling him to come back: he was looking at his watch the whole time, still is.’

‘And where is he now?’ Hanne hadn’t taken her eyes off the map of Frankfurt. Her finger was running along Moselstrasse.

‘Seems he’s in a queue in Elbe Strasse. There… the street behind.’

Her finger traced the map to Elbe Strasse. ‘And they’re watching him?’

‘Of course.’

They were in the control room in the building on Fürstenbergerstrasse as the messages came through intermittently from Sorensen’s team following Charles Falmer.

Subject is still queuing for soup on Elbe Strasse, appears nervous.

Subject has purchased soup and is drinking it in a doorway, keeps looking at watch.

Subject on the move and…

The last message had broken up: the radio operator said it was distorted and they’d have to wait. The room filled with the sound of static, and Hanne stared at the operator as if it was his fault. It was five minutes before the messages resumed.

Subject is now back in Moselstrasse: has returned to potato stall.

Subject has moved into building behind potato stall: no longer in sight.

‘They’re going to lose them. Shouldn’t they move in?’

‘Be patient, Richard.’ Hanne placed her hand on Prince’s arm. ‘They have the building covered.’

‘But with the cellars… he could slip away.’

Sorensen assured them no one would slip away from his team of watchers and remained calm as Prince paced the room and Hanne glared at the map and the radio operator in turn. The tension was broken by a burst of static followed by a deep voice.

Subject is leaving potato stall and now on Moselstrasse – following.

Subject now on Kaiserstrasse and heading west in direction of Hauptbahnhof.

Sorensen instructed the radio operator to tell them to keep watching the potato stall too.

Subject now crossing Hohenzollern Strasse and about to enter station.

Man carrying a rucksack and wearing a leather jacket and a woollen hat now leaving stall. Appears to have just one arm: request instructions.

‘Did I hear him say it was a one-armed man?’

‘Yes.’

‘In that case, we have to follow both him and Falmer.’

‘That’s just what I was about to tell them.’

Ulrich had been shocked when he received the telephone call to tell him the courier had turned up at Moselstrasse. When he had failed to appear as arranged on Elsa-Brändström-Platz, he’d assumed that was it, and when he heard he’d been arrested by the Americans and was being held at IG Farben, he’d feared the worst.