“It wouldn’t happen to be her mother’s house where you had the helium, tubing and gloves delivered, would it?” asked Robin.

Raphael blinked. He hadn’t expected that.

“You needed an address that didn’t seem connected to you. You made sure it was delivered while the owners were away, or at work, then you could let yourself in, collect the failed delivery card…”

“Pick it up, disguised and get it couriered it off to dear old Dad’s house, yeah.”

“And Flick took delivery and Kinvara made sure she hid it from your father until it was time to kill him?”

“That’s right,” said Raphael. “You pick up a lot of tips in jail. Fake IDs, vacant buildings, empty addresses, you can do a hell of a lot with them. Once you’re dead—” Robin’s scalp prickled—“nobody’s going to connect me with any of the addresses.”

“The owner of this barge—”

“Is going to be telling everyone she was having sex with me in Drummond’s bathroom, remember? She’s on my team, Venetia,” he said quietly, “so it’s not looking good for you, is it?”

“There were other mistakes,” said Robin, her mouth dry.

“Like?”

“You told Flick your father needed a cleaner.”

“Yeah, because it makes her and Jimmy look fishy as hell, that she wheedled her way into my father’s house. The jury’ll be focused on that, not how she found out he wanted a cleaner. I’ve already told you, she’s going to look like a grubby little tart with a grudge in the dock. That’s just one more lie.”

“But she stole a note from your father, a note he wrote while he was trying to check Kinvara’s story with Le Manoir aux Quat’Saisons. I found it in her bathroom. She’d lied, told him her mother was going to the hotel with her. They’d never normally give out information about guests, but he was a government minister and he’d previously been there, so we think he managed to trick them into agreeing that they could remember the family vehicle there and that it was a shame her mother hadn’t made it. He made a note of the suite Kinvara was in, probably pretending he’d forgotten it, and he was trying to get hold of the bill, to see whether there was any sign of two lots of breakfast or dinner, I suppose. When the prosecution produce the note and the bill in court—”

“You found that note, did you?” said Raphael.

Robin’s stomach turned over. She had not meant to give Raphael another reason to shoot her.

“I knew I’d underestimated you after that dinner we had, at Nam Long Le Shaker,” said Raphael. It wasn’t a compliment. His eyes were narrowed, his nostrils flared in dislike. “You were a mess, but you were still asking fucking inconvenient questions. You and your boss were cozier with the police than I expected, too. And even after I tipped off the Mail—”

“That was you,” said Robin, wondering how she had never realized. “You put the press and Mitch Patterson back on us…”

“I told them you’d left your husband for Strike, but that he was still shagging his ex. Izzy had given me that bit of gossip. I thought you needed slowing down, you two, because you kept poking away at my alibi… but after I’ve shot you,”—an icy chill ran the length of Robin’s body—“your boss’ll be busy answering the press’s questions about how your body ended up in a canal, won’t he? I think that’s called killing two birds with one stone.”

“Even if I’m dead,” said Robin, her voice as steady as she could make it, “there’ll still be your father’s note and the hotel’s testimony—”

“OK, so he was worried about what Kinvara was doing at Le Manoir,” said Raphael roughly. “I’ve just told you, nobody saw me on the premises. The stupid cow did ask for two glasses with the champagne, but she could’ve been with someone else.”

“You aren’t going to have any opportunity to cook up a new story with her,” said Robin, her mouth drier than ever, her tongue sticking to the roof of her mouth as she tried to sound calm and confident. “She’s in custody now, she isn’t as clever as you—and you made other mistakes,” Robin rushed on, “stupid ones, because you had to enact the plan in a hurry once you realized your father was onto you.”

“Like?”

“Like Kinvara taking away the packaging on the amitriptyline, after she’d doctored the orange juice. Kinvara forgetting to tell you the trick to closing the front door properly. And,” said Robin, aware that she was playing her very last card, “her throwing the front door key to you, at Paddington.”

In the wordless space that now stretched between them, Robin thought she heard footsteps close at hand. She didn’t dare look out of the window in case she alerted Raphael, who appeared too appalled by what she had just said to take in anything else.

“‘Throwing the front door key to me?’” repeated Raphael, with fragile bravado. “What the hell are you talking about?”

“The keys to Ebury Street are restricted, almost impossible to copy. The pair of you only had access to one: hers, because your father was suspicious of you both by the time he died, and he’d made sure the spare was out of your reach.

“She needed the key to get into the house and doctor the orange juice and you needed it to go in early next morning and suffocate him. So you cobbled together a plan at the last minute: she’d pass you the key at a prearranged spot at Paddington, where you’d be disguised as a homeless person.

“You were caught on camera. The police have got people enlarging and clarifying the image right now. They think you must have bought things from a charity shop in haste, which might produce another useful witness. The police are now combing CCTV footage for your movements from Paddington onwards.”

Raphael said nothing at all for nearly a minute. His eyes were moving fractionally from left to right, as he tried to find a loophole, an escape.

“That’s… inconvenient,” he said finally. “I didn’t think I was on camera, sitting there.”

Robin thought she could see hope slipping away from him now. Quietly, she continued, “As per your plan, Kinvara arrived home in Oxfordshire, called Drummond and left a message that she wanted the necklace valued, to set up that whole back-up story.

“Early next morning, another burner phone was used to call both Geraint Winn and Jimmy Knight. Both were lured out of their houses, presumably with a promise of information on Chiswell. That was you, making sure they were in the frame if murder was suspected.”

“No proof,” muttered Raphael automatically, but still his eyes darted this way and that, searching for invisible lifelines.

“You let yourself into the house very early in the morning, expecting to find your father almost comatose after his early morning orange juice, but—”

“He was out of it, at first,” said Raphael. His eyes had become glazed, and Robin knew that he was remembering what had happened, watching it, inside his head. “He was slumped on the sofa, very groggy. I walked straight past him into the kitchen, opened my box of toys—”

For a sliver of a second, Robin saw again the shrink-wrapped head, the gray hair pressed around the face so that only the gaping black hole of the mouth was visible. Raphael had done that; Raphael, who currently had a gun pointing at her face.