At just past nine o’clock, she heard, with a wave of nausea, Matthew’s key in the lock and the sound of the door opening.

“Sorry,” he shouted, before he’d even closed the door, “he’s a silly sod, I had a job persuading the taxi driver to take—”

Robin heard his small exclamation of surprise as he spotted the suitcases. Safe, now, to dial, she pressed the number she had ready on her phone. He walked into the sitting room, puzzled, in time to hear her booking a minicab. She hung up. They looked at each other.

“What’s with the cases?”

“I’m leaving.”

There was a long silence. Matthew seemed not to understand.

“What d’you mean?”

“I don’t know how to say it any more clearly, Matt.”

“Leaving me?”

“That’s right.”

“Why?”

“Because,” said Robin, “you’re sleeping with Sarah.”

She watched Matthew struggling to find words that might save him, but the seconds slid by, and it was too late for real incredulity, for astonished innocence, for genuine incomprehension.

“What?” he said at last, with a forced laugh.

“Please don’t,” she said. “There’s no point. It’s over.”

He continued to stand in the doorway of the sitting room and she thought he looked tired, even haggard.

“I was going to go and leave a note,” said Robin, “but that felt too melodramatic. Anyway, there are practical things we need to talk about.”

She thought she could see him thinking, How did I give it away? Who have you told?

“Listen,” he said urgently, dropping his sports bag beside him (full, no doubt, of clean, pressed kit), “I know things haven’t been good between us, you and me, but it’s you I want, Robin. Don’t throw us away. Please.”

He walked forwards, dropped into a crouch beside her chair and tried to take her hand. She pulled it away, genuinely astonished.

“You’re sleeping with Sarah,” she repeated.

He got up, crossed to the sofa and sat down, dropped his face into his hands and said weakly:

“I’m sorry. I’m sorry. It’s been so shit between you and me—”

“—that you had to sleep with your friend’s fiancée?”

He looked up at that, in sudden panic.

“Have you spoken to Tom? Does he know?”

Suddenly unable to bear his proximity, she walked away towards the window, full of a contempt she had never felt before.

“Even now, worried about your promotion prospects, Matt?”

“No—fuck—you don’t understand,” he said. “It’s over between me and Sarah.”

“Oh, really?”

“Yes,” he said. “Yes! Fuck—this is so fucking ironic—we talked all day. We agreed it couldn’t go on, not after—you and Tom—we’ve just ended it. An hour ago.”

“Wow,” said Robin, with a little laugh, feeling disembodied, “isn’t that ironic?”

Her mobile rang. Dreamlike, she answered it.

“Robin?” said Strike. “Update. I’ve just seen Della Winn.”

“How did it go?” she asked, trying to sound steady and bright, determined not to cut the call short. Her working life was now her entire life and Matthew would no longer impinge upon it. Turning her back on her fuming husband, she looked out onto the dark cobbled street.

“Very interesting on two counts,” said Strike. “Firstly, she slipped up. I don’t think Geraint was with Aamir the morning Chiswell died.”

“That is interesting,” said Robin, forcing herself to concentrate, aware of Matthew watching her.

“I’ve got a number for him and I tried it, but he’s not picking up. I thought I’d see if he’s still at the B&B down the road as I’m in the vicinity, but the owner says he’s moved on.”

“Shame. What was the other interesting thing?” asked Robin.

“Is that Strike?” asked Matthew loudly, from behind her. She ignored him.

“What was that?” asked Strike.

“Nothing,” said Robin. “Go on.”

“Well, the second interesting thing is that Della met Kinvara last year, who was hysterical because she thought Chiswell—”

Robin’s mobile was pulled roughly out of her hand. She wheeled around. Matthew ended the call with a stab of his finger.

“How dare you?” shouted Robin, holding out her hand. “Give that back!”

“We’re trying to save our fucking marriage and you’re taking calls from him?”

“I’m not trying to save this marriage! Give me back my phone!”

He hesitated, then thrust it back at her, only to look outraged when she coolly phoned Strike back again.

“Sorry about that, Cormoran, we got cut off,” she said, with Matthew’s wild eyes on her.

“Everything all right there, Robin?”

“It’s fine. What were you saying about Chiswell?”

“That he was having an affair.”

“An affair!” said Robin, her eyes on Matthew’s. “Who with?”

“Christ knows. Have you had any luck getting hold of Raphael? We know he’s not that bothered about protecting his father’s memory. He might tell us.”

“I left a message for him, and for Tegan. Neither of them have called back.”

“OK, well, keep me posted. This all sheds an interesting light on the hammer round the head, though, doesn’t it?”

“Certainly does,” said Robin.

“That’s me at the Tube. Sure you’re all right?”

“Yes, of course,” said Robin, with what she hoped sounded like workaday impatience. “Speak soon.”

She hung up.

“‘Speak soon,’” Matthew imitated her, in the high-pitched, wispy voice he always used when impersonating women. “‘Speak later, Cormoran. I’m running out on my marriage so I can be at your beck and call forever, Cormoran. I don’t mind working for minimum wage, Cormoran, not if I can be your skivvy.’”

“Fuck off, Matt,” said Robin calmly. “Fuck off back to Sarah. The earring she left in our bed is upstairs on my bedside table, by the way.”

“Robin,” he said, suddenly earnest, “we can get through this. If we love each other, we can.”

“Well, the problem with that, Matt,” said Robin, “is that I don’t love you anymore.”

She had always thought the idea of eyes darkening was literary license, but she saw his light eyes turn black as his pupils dilated in shock.

“You bitch,” he said quietly.

She felt a cowardly impulse to lie, to back away from the absolute statement, to protect herself, but something stronger in her held on: the need to tell the unvarnished truth, when she had been lying to him and herself for so long.

“No,” she said. “I don’t. We should have split up on the honeymoon. I stayed because you were ill. I felt sorry for you. No,” she corrected herself, determined to do the thing properly, “actually, we should never have gone on the honeymoon. I ought to have walked out of the wedding once I knew you’d deleted those calls from Strike.”