He was at the front door when, on impulse, he turned back and said to Meg Dennison: 'I think you mentioned that you walked from the Old Rectory, Mrs Dennison.

Gould I walk home with you, that is if it's not too early for you?'

Alex Mair was beginning to say that he, of course, would drive her but Meg extricated herself clumsily from her chair and said, a little too eagerly: 'I'd be grateful if you would. I would like the walk and it would save Alex getting out the car.'

Alice Mair said: 'And it's time Theresa was on her way. We should have driven her home an hour ago. I'll give her father a ring. Where is she, by the way?'

Meg said: 'I think she was next door clearing the table a minute ago.'

'Well, I'll find her and Alex can drive her home.'

The party was breaking up. Hilary Robarts had been slumped back in her chair, her eyes fixed on Lessingham. Now she got to her feet and said: 'I'll get back to my cottage. There's no need for anyone to come with me. As Miles has said, the Whistler's had his kicks for tonight.'

Alex Mair said: 'I'd rather you waited. I'll walk with you once I've taken Theresa home.'

She shrugged and, without looking at him, said: 'All right, if you insist. I'll wait.'

She moved over to the window, staring out into the darkness. Only Lessingham stayed in his chair, reaching again to fill his glass. Dalgliesh saw that Alex Mair had silently placed another opened bottle in the hearth. He wondered whether Alice Mair would invite Lessingham to stay the night at Martyr's Cottage or whether he would be driven home later by her or her brother. He would certainly be in no state to drive himself.

Dalgliesh was helping Meg Dennison into her jacket when the telephone rang, sounding unnaturally strident in the quiet room. He felt her sudden shock of fear and for a moment, almost involuntarily, his hands strengthened on her shoulders. They heard Alex Mair's voice.

'Yes, we've heard. Miles Lessingham is here and gave us the details. Yes, I see. Yes. Thank you for letting me

know.' Then there was a longer silence, then Mair's voice again. 'Completely fortuitous, I should say, wouldn't you? After all, we have a staff of five hundred and thirty. But naturally everyone at Larksoken will find the news deeply shocking, the women particularly. Yes, I shall be in my office tomorrow if there's any help I can give. Her family have been told, I suppose? Yes, I see. Good night, Chief Inspector.'

He put down the receiver and said: 'That was Chief Inspector Rickards. They've identified the victim. Christine Baldwin. She is – she was – a typist at the station. You didn't recognize her then, Miles?'

Lessingham took his time refilling his glass. He said: 'The police didn't tell me who she was. Even if they had, I wouldn't have remembered the name. And no, Alex, I didn't recognize her. I suppose I must have seen Christine Baldwin at Larksoken, probably in the canteen. But what I saw earlier tonight wasn't Christine Baldwin. And I can assure you that I didn't shine the torch on her longer than I needed to satisfy myself that she was beyond any help that I could give.'

Without looking round from the window Hilary Robarts said: 'Christine Baldwin. Aged thirty-three. Actually, she's only been with us for eleven months. Married last year. Just transferred to the medical physics department. I can give you her typing and shorthand speeds if you're interested.' Then she turned round and looked Alex Mair in the face. 'It looks as if the Whistler's getting closer, doesn't it, in more ways than one.'

The final goodbyes were said and they stepped out from the smell of wood smoke, food and wine from a room which Dalgliesh was beginning to find uncomfortably warm into the fresh, sea-scented air. It took a few minutes before his eyes had adjusted to semi-darkness and the great sweep of the headland became visible, its shapes and forms mysteriously altered under the high stars. To the north the power station was a glittering galaxy of white lights, its stark geometric bulk subsumed in the blue-black of the sky.

They stood for a moment regarding it, then Meg Dennison said: 'When I first came here from London it almost frightened me, the sheer size of it, the way it dominates the headland. But I'm getting used to it. It's still disturbing but it does have a certain grandeur. Alex tries to demystify it, says its function is just to produce electricity for the National Grid efficiently and cleanly, that the main difference between this and any other power station is that you don't have beside it a huge pyramid of polluting coal dust. But atomic power to my generation always means that mushroom cloud. And now it means Chernobyl. But if it were an ancient castle standing there against the skyline, if what we looked out at tomorrow morning was a row of turrets, we'd probably be saying how magnificent it is.'

Dalgliesh said: 'If it had a row of turrets it would be a rather different shape. But I know what you mean. I should prefer the headland without it but it's beginning to look as if it had a right to be there.'

They turned simultaneously from contemplating the glittering lights and looked south to the decaying symbol of a very different power. Before them, at the edge of the cliff, crumbling against the skyline like a child's sandcastle rendered amorphous by the advancing tide, was the ruined

Benedictine abbey. He could just make out the great empty arch of the east window and beyond it the shimmer of the North Sea while above, seeming to move through and over it like a censer, swung the smudged yellow disc of the moon. Almost without conscious will they took their first steps from the track on to the rough headland towards it. Dalgliesh said: 'Shall we? Can you spare the time? And what about your shoes?'

'Reasonably sensible. Yes, I'd like to, it looks so wonderful at night. And I don't really need to hurry. The Copleys won't have waited up for me. Tomorrow, when I have to tell them how close the Whistler is getting, I may not like to leave them alone after dark. This may be my last free night for some time.'

'I don't think they'd be in any real danger as long as you lock up securely. So far all his victims have been young women and he kills out of doors.'

'I tell myself that. And I don't think they'd be seriously frightened. Sometimes the very old seem to have moved beyond that kind of fear. The trivial upsets of daily living assume importance but the big tragedies they take in their stride. But their daughter is constantly ringing up to suggest they go to her in Wiltshire until he's caught. They don't want to but she's a strong-minded woman and very insistent, and if she telephones after dusk and I'm not there it will increase the pressure on them.' She paused and then said: 'It was a horrible end to an interesting but rather strange dinner party. I wish Mr Lessingham had kept the details to himself, but I suppose it helped him to talk about it, especially as he lives alone.'

Dalgliesh said: 'It would have needed superhuman control not to have talked about it. But I wish he'd omitted the more salacious details.'

'It will make a difference to Alex, too. Already some of the women staff demand to be escorted home after the evening shifts. Alice has told me that that isn't going to be easy for Alex to organize. They'll only accept a male escort if he has an unbreakable alibi for one of the Whistler murders. People cease to be rational even when they've known and worked with someone for the last ten years.'

Dalgliesh said: 'Murder does that, particularly this kind of murder. Miles Lessingham mentioned another death: Toby. Was that the young man who killed himself at the station? I seem to remember a paragraph in one of the papers.'

'It was an appalling tragedy. Toby Gledhill was one of Alex's most brilliant young scientists. He broke his neck by throwing himself down on top of the reactor.'