‘If it was anyone, it had to be either you or him, John,’ Banks said later back in his office, while Owen Doughton was being charged downstairs. ‘Only the two of you were intimate enough with Anna to know her habits, her routines. And Owen had lived with her until quite recently. There was a chance he still had a key.’

John Billings shook his head. ‘I thought you were arresting me.’

‘It was touch and go, I won’t deny it. But at least I thought I’d give you a chance, the benefit of the doubt.’

‘And if your trap hadn’t worked?’

Banks shrugged. ‘Down to you, I suppose. The poison could have been anywhere, in anything. Toothpaste, for example. I knew if it wasn’t you, and the killer heard the news, he’d try to destroy any remaining evidence. He wouldn’t have had a chance to do so yet because you were in the house.’

‘But I was at the hospital nearly all yesterday.’

‘Too soon. He had no idea anything had happened at that time. This wasn’t a carefully calculated plan.’

‘But why?’

Banks shook his head. ‘That I can’t say for certain. He’s a sick man, an obsessed man. It’s my guess it was his warped form of revenge. It had been eating away at him for some time. Anna didn’t treat him very well, John. She didn’t really stop to take his feelings into account when she kicked him out and took up with you. She just assumed he would understand, like he always had, because he loved her and had her welfare at heart. He was deeply hurt, but he wasn’t the kind to make a fuss or let his feelings show. He kept it all bottled up.’

‘She could be a bit blinkered, could Anna,’ John mumbled. ‘She was a very focused woman.’

‘Yes. And I’m sure Doughton felt humiliated when she dumped him and turned to you. After all, he didn’t have much of a financial future, unlike you.’

‘But it wasn’t that, not with Anna,’ Billings protested. ‘We just had so much in common. Goals, tastes, ambitions. She and Owen had nothing in common any more.’

‘You’re probably right,’ Banks said. ‘Anyway, when she told him a couple of weeks ago that she was going to get married to you, it was the last straw. He said she expected him to be happy for her.’

‘But why did he keep on seeing her if it hurt him so much?’

‘He was still in love with her. It was better seeing her, even under those circumstances, than not at all.’

‘Then why kill her?’

Banks looked at Billings. ‘Love and hate, John,’ he said. ‘They’re not so far apart. Besides, he doesn’t believe he did kill her, that wasn’t really his intention at all.’

‘I don’t understand. You said he did. How did he do it?’

Banks paused and lit a cigarette. This wasn’t going to be easy. Rain blew against the window and a draught rattled the Venetian blind.

‘How?’ Billings repeated.

Banks looked at his calendar, trying to put off the moment; it showed a woodland scene, snowdrops blooming near The Strid at Bolton Abbey. He cleared his throat. ‘Owen came to the house while you were both out,’ Banks began. ‘He brought a syringe loaded with a strong pesticide he got from the garden centre. Remember, he knew Anna intimately. Did you and Anna make love that night, John?’

Billings reddened. ‘For Christ’s sake-’

‘I’m not asking whether the earth moved, I’m just asking if you did. Believe me, it’s relevant.’

‘All right,’ said Billings after a pause. ‘Yes, we did, as a matter of fact.’

‘Owen knew Anna well enough to know that she was frightened of getting pregnant,’ Banks went on, ‘but she wouldn’t take the pill because of the side effects. He knew she insisted on condoms, and he knew she liked to make love in the dark. It was easy enough to insert the needle into a couple of packages and squirt in some pesticide. Not much, but it’s very powerful stuff, colourless and odourless, so even an infinitesimal coating would have some effect. The condoms were lubricated, so they’d feel oily anyway, and nobody would notice a tiny pinprick in the package. You absorbed a little into your system, too, and that’s why you felt ill. You see, it’s easily absorbed through skin or membranes. But Anna got the lion’s share. Dr Glendenning would have found out eventually how the poison was administered from tissue samples, but further tests would have taken time. Owen could easily have nipped back to the house and removed the evidence by then. Or we might have decided that you had better access to the method.’

Billings paled. ‘You mean it could just as easily have been me either killed or arrested for murder?’

Banks shrugged. ‘It could have turned out any way, really. There was no way of knowing accurately what would happen, and certainly there was a chance that either you would die or the blame would fall on you. As it turned out, Anna absorbed most of it, and she had asthma. In Owen’s twisted mind, he wanted your love-making to make you sick. That was his statement, if you like, after suffering so long in silence, pretending it was OK that Anna had moved on. But that’s all. It was a sick joke, if you like. We found three poisoned condoms. Certainly if one hadn’t worked the way it did, there could have been a build up of the pesticide, causing chronic problems. I did read about a case once,’ Banks went on, ‘where a man married rich women and murdered them for their money by putting arsenic on his condoms, but they were made of goatskin back then. Besides, he was French. I’ve never come across a case quite as strange as this.’

Billings shook his head slowly. ‘Can I go now?’ he asked.

‘Where to?’

‘I don’t know. A hotel, perhaps, until…’

Banks nodded and stood up. As they went down the stairs, they came face to face with Owen Doughton, handcuffed to a large constable. Billings stiffened. Doughton glared at him and spoke to Banks. ‘He’s the one who killed her,’ he said, with a toss of his head. ‘He’s the one you should be arresting.’ Then he looked directly at Billings. ‘You’re going to have to live with that, you know, Mr Moneybags. It was you who killed her. Hear that, Mr Yuppie Moneybags? You killed her. You killed Anna.’

Banks couldn’t tell whether he was laughing or crying as the constable led him down to the cells.

People go missing all the time in war, of course, but not usually nine-year-old boys. Besides, the war had hardly begun. It was only 20 September 1939 when Mary Critchley came hammering on my door at about three o’clock, interrupting my afternoon nap.

It was a Wednesday, and normally I would have been teaching the fifth-formers Shakespeare at Silverhill Grammar School (a thankless task if ever there was one), but the Ministry had just got around to constructing airraid shelters there, so the school was closed for the week. We didn’t even know if it was going to reopen because the plan was to evacuate all the children to safer areas in the countryside. Now I would be among the first to admit that a teacher’s highest aspiration is a school without pupils, but in the meantime the government, in its eternal wisdom, put us redundant teachers to such complex, intellectual tasks as preparing ration cards for the Ministry of Food. (After all, they knew what was coming.)

All this was just a small part of the chaos that seemed to reign at that time. Not the chaos of war, the kind I remembered from the trenches at Ypres in 1917, but the chaos of government bureaucracies trying to organize the country for war.

Anyway, I was fortunate enough to become a Special Constable, which is a rather grandiose title for a sort of part-time dogsbody, and that was why Mary Critchley came running to me. That and what little reputation I had for solving people’s problems.

‘Mr Bashcombe! Mr Bashcombe!’ she cried. ‘It’s our Johnny. He’s gone missing. You musht help.’