‘From what I can tell, Agent Horatio is genuine, although of course that can’t be guaranteed. I’ve watched him the last two mornings and he appears to have a routine – the time he leaves his apartment, the route he takes to his office, the café he stops at on the way for breakfast. You’ll bump into him on that route; I’ve identified the best place to do it. I’ll explain.’

Prince could feel his heart beating fast. It was a feeling of fear mixed with a growing excitement. It also meant he’d be able to leave an apartment he’d been confined to for too long. The walls had begun to close in on him.

‘When will I be bumping into him?’

‘Tomorrow morning.’

From the north bank of the Nyhavn canal he watched Otto Knudsen leave his building on the south bank. Everything was precisely as Hanne had described it. Knudsen, a tall, smartly dressed man in a dark trilby-style hat with a wide brim and a long light brown raincoat, left the building a shade after eight o’clock. He turned left and walked briskly along the canal, past the junction with Heibergsgade and towards Kongens Nytorv, a large square where Prince recalled having lunch with his grandparents in another life.

Agent Horatio will enter the square and turn right. He’ll then turn left and go into one of the cafés on the north side. If you follow him, you’ll be able to see where he goes. Try and approach him as he goes into the café. If it doesn’t feel right, wait until he leaves it.

Prince fell into step with the other man. As they approached Kongens Nytorv, Knudsen quickened his step. Only when it was too late did Prince notice a queue in front of him on the north side of the canal, as Nyhavn joined the square.

It was a German checkpoint.

He had no alternative but to stay in the queue, gathering his thoughts as he did so. He realised he now wouldn’t be able to pick up Knudsen before he entered the café. Hopefully he’d be able to spot which one he was in and approach after he’d left it. He tried to remain calm. He was confident he knew every aspect of his Jesper Holm identity; after all, he’d had plenty of time in the apartment to study it over and over again.

And he remembered what he’d been told in Matlock: Checkpoints are routine in occupied Europe. Unfortunately, they’re part of everyday life. The most important thing to remember about a checkpoint is not to panic. Do not under any circumstances try and leave the queue – they watch out for people doing precisely that.