Up in the lantern room, I went straight to the speaking tube, carefully removed the brass whistle and put the funnelled end to my ear. I sat down, trying not to breathe too loudly. I stared out through the glass into the blue of the day, and listened.

‘I had been waiting to hear from you, Mr Smith.’ That was Pinstripe. He must have been sitting a bit further away from the speaking tube – on the other side of the table; his voice was quieter than Pa’s.

‘Waiting? Then you knew?’

I caught my breath. Knew what?

‘I’ve had suspicions since I came here to the lighthouse on the day of your wife’s tribunal. We took one of your old logbooks, and I’ve been comparing your charts with the diagrams we seized.’

‘Ah.’

A cold, sick feeling started spreading through my body.

‘I needed stronger proof and was about to bring you in for questioning when I received your telephone call.’

Proof? Was he saying it was Pa? That Pa was the traitor? But . . .

‘I only sent that one package, sir. Just one package of information.’

My heart pounded so hard I thought it might burst. I saw that the blood from the cut under my thumbnail was soaking, bright red, through the cloth.

‘But why, Mr Smith? You’re not on the side of the Nazis, are you?’

Of course he’s not, I wanted to scream down the tube. Of course he’s not! I pressed my clammy hand over my mouth to stop myself from screaming it out loud.

But Pa didn’t say anything.

‘Why now? Why tell me the truth now?’

Pa cleared his throat. ‘You know why. My wife has made a confession. And with the new Treachery Act – the sentence . . . It’s all lies, of course – her confession. She must be trying to protect me. She must have found out somehow.’

‘Yes, perhaps,’ Pinstripe said. ‘She is certainly trying to protect someone. I went to see her yesterday and told her we wouldn’t be using her confession as evidence, as it clearly wasn’t true. She was not able to replicate the diagrams or even explain the meaning of the shipping coordinates.’

The world beyond the window was a swimming haze of sea and sky. I felt as if I were clinging to the top of a mast, swaying sickeningly above the real world. It was all too much – Mutti’s confession, and now Pa’s. It seemed now that Mutti’s life was saved, but Pa – my Pa . . .

‘Why did you do it, Mr Smith? Who contacted you?’

Pa said nothing for a few moments. Then he just said, ‘I had no choice. That is all I am able to say, Inspector. I had no choice.’

‘What do you mean exactly?’

‘I mean that if you were torn between loyalty to your country and love for your family, what would you choose? What would you actually choose?’