“She’s wearing the necklace, isn’t she?” I feel a flicker of frustration. “She kept it all her life. How much more evidence do you need?”

“Does the necklace still exist?” His eyes bulge again. “Do you have it? Is she still alive?” As this new thought occurs to him, his eyes nearly pop out of his head. “Because that would really be-”

“She’s just died, I’m afraid.” I cut him off before he can get too excited. “And I don’t have the necklace. But I’m trying to track it down.”

“Well.” Malcolm Gledhill takes out a paisley handkerchief and wipes his perspiring brow. “Clearly, in a case like this, much careful inquiry and research is required before we can come to any definitive conclusion-”

“It’s her,” I say firmly.

“So I’ll refer you, if I may, to our research team. They will look at your claim very carefully, study all the evidence available.”

He needs to play the official game properly. I can understand that.

“I’d love to talk to them,” I say politely. “And I know they’ll agree with me. It’s her.”

I suddenly spot a postcard of Girl with a Necklace stuck on his computer with Blu-Tack. I take it down and lay it beside the photo of Sadie from the nursing home. For a moment we both look silently at the two images. Two radiant, proud eyes in one picture; two hooded, ancient eyes in the other. And the necklace glimmering, a constant talisman, linking the two.

“When did your great-aunt die?” says Malcolm Gledhill at last, his voice soft.

“A few weeks ago. But she lived in a nursing home since the 1980s, and she didn’t know much about the outside world. She never knew Stephen Nettleton became famous. She never knew that she was famous. She thought she was a nobody. And that’s why I want the world to know her name.”

Malcolm Gledhill nods. “Well, if the research team comes to the conclusion that she was the sitter in the portrait… then, believe me, the world will know her name. Our marketing team did some research recently, and it turns out Girl with a Necklace is the most popular portrait in the gallery. They want to expand her profile. We consider her an exceedingly valuable asset.”

“Really?” I flush with pride. “She’d have loved to know that.”

“May I call in a colleague to see this photograph?” His eyes brighten. “He has a special interest in Malory, and I know he will be extremely interested in your claim-”

“Wait.” I hold up a hand. “Before you call in anyone else, there’s another issue I need to talk to you about. In private. I want to know how you got the painting in the first place. It belonged to Sadie. It was hers. How did you get it?”

Malcolm Gledhill stiffens very slightly.

“I thought this matter might arise at some stage,” he says. “Following your phone call, I went and retrieved the file, and I’ve looked up the details of the acquisition.” He opens a file, which has been sitting on the desk all this while, and unfolds an old piece of paper. “The painting was sold to us in the 1980s.”

Sold? How could it have been sold?

“But it was lost after a fire. No one knew where it was. Who on earth sold it to you?”

“I’m afraid…” Malcolm Gledhill pauses. “I’m afraid the vendor asked at the time that all details of the acquisition should be kept confidential.”

“Confidential?” I stare at him in outrage. “But the painting was Sadie’s. Stephen gave it to her. Whoever got hold of it didn’t have the right to sell it. You should check these things!”

“We do check these things,” says Malcolm Gledhill, a little defensively. “All the provenance was deemed to be correct at the time. The gallery went to all reasonable lengths to determine that the painting was the vendor’s to sell. Indeed, a letter was signed in which the vendor made all the correct assurances. I have it here.”

His eyes keep dropping down to the paper in his hand. He must be looking at the name of whoever sold it. This is totally maddening.

“Well, whatever that person said to you, they were lying.” I glare at him. “And you know what? I’m a taxpayer, and I fund you lot. In fact, in a way, I own you lot. And I hereby demand to know who sold it to you. At once.”

“I’m afraid you’re mistaken,” says Malcolm Gledhill mildly. “We are not a publicly owned gallery, and you don’t own us. Believe me, I would like to clear this matter up as much as you would. But I am bound by our confidentiality agreement. I’m afraid my hands are tied.”