“I mean that if Morna hadn’t told us she’d seen him, Wim mightn’t have jumped to the conclusion the half-Asian boy and the blond woman he saw were Jason and Alison. Sorry, Wim, I’m only saying we took our cue from you. We wanted them to be those people and we jumped to a conclusion too.”

Wim said slowly, “There’s a way to prove it.”

We listened.

“We show ourselves to them.” His strange pan-European accent had become more marked. “The boy’s not important. That is, not for our purposes. Your purposes. We go to the balcony and show ourselves to the man and the woman, preferably together but one or other of them will do.”

I must have been very slow that night for I asked what for. “They won’t recognize us.”

“I think I know what Wim means,” Silver said. “If they see us—and remember, they’ll be seeing three young people, dirty and in grotty clothes from crawling along that balcony—if they see us outside their window looking in, maybe even threatening to break in, and if they’re law-abiding respectable people called, for example, Robinson, they’ll ring the police. Anyone not afraid of the law would.”

Wim smiled. “But if they’re who I think they are, they’ll be more afraid of the police than of us. They won’t call them. They’ll prepare themselves to put up a fight.”

“We may as well do it now.” Silver got to his feet and put out his hand to pull me to mine. “Down one lot of scaffolding and up the other.”

It was dark and windy, the sky covered by a lumpy wrack of cloud that, lit from below, looked like cottage cheese stained with purple juice. The wind came in occasional sharp gusts, bringing a short splash of rain with it, but otherwise the air was still and damp. It was dangerous walking on the slates, though nothing would have made me say so. I was relieved when we slid off the mansard onto the narrow walkway between parapet and house wall.

Why did we want to do it? To identify them? Most of all, why did we want to help them? We didn’t know them. We knew virtually nothing about the way adoption worked in this country, I don’t suppose we even knew that no central agency existed and that adoption was managed by local authorities— if, indeed, we knew what a local authority was and did. Such knowledge as we had came from reading about Andrew Lane and Alison Barrie in the newspapers. So why did we place ourselves so firmly on their side and against those forces that wanted to take Jason away from them?