Nightfall was the snakes' greatest ally. They could have been lying low further down by day and with the coming of darkness they might start to move. Upwards. So tomorrow whilst the searchers toiled down below, their prey could be safely ensconced several hundred feet above them up on the moorland.

But not all of them, John Price was adamant about that. They were not hunting a flock of snakes, rather six very different species. The pairs would stay together in all probability. But nobody really knew, they could only guess. The killers were in a strange alien environment and there was no way of knowing how they might react. There was no book of rules to consult.

John heard the whine of the helicopters again. The choppers were flying low, sweeping the grassy slopes, determined not to give up until the light was gone altogether. A long shot, but when lives were at stake you played every card you had.

'We'll have to call it a day,' the sweat-grimed colonel was polishing his spectacles, dejection in his tone, head bowed as though their failure to find the snakes was a personal affront to his own rank and status. 'We'll make an early start in the morning. 7 a.m. Everybody assemble at the police station. It's the hillsides and slopes tomorrow, working back towards the village. The choppers will be out before then, scouring. We can only hope.'

Chief Inspector Watts nodded but declined to comment. Everybody knew the position, the colonel had said everything there was to be said. Surely the reptiles had to show up somewhere; the worrying factor was just where.

It was 10.05 when John Price disembarked from the camouflaged army Land Rover and began to walk the length of the village in the direction of Aunt Elsie's bungalow. His feet dragged but mentally he was still alert. On a balmy summer evening such as this he would have expected to see families enjoying the late evening in deck-chairs in their gardens or taking a stroll before going to bed. The main street was deserted, lights showing in some of the houses on either side.

He passed the Rising Sun. The beer-garden at the side was deserted, an air of desolation about the array of white-painted tables and chairs, an empty glass tipped over with insects crawling inside it after the dregs; you had the feeling that it had been like that since yesterday, that nobody had ventured out there. Stay indoors and be safe, never mind the stifling atmosphere, that's a small price to pay for your life.

There were people in the bar, he heard their voices and the wafting aroma of beer almost tempted him inside. God, he could swallow a pint of lager at one go. But the thought of his aunt all alone dissuaded him. She would doubtless be worrying, probably had been all day and he was later than he had anticipated. The trouble with Elsie Harrison was that she was always so precise—what time will you be home, John? Even when he just popped out for a quick half.

Between ten and half past meant she started looking out for him at five to ten. He had not failed to notice the pack of low-alcohol shandies lined up on the shelf in the fridge, a subtle move on her part to keep him in at nights, depriving him of that one half-hour of freedom down at the Rising Sun. But nobody had bargained for this crisis. And John Price would stay in Stainforth until every one of those poisonous creatures was accounted for.

He noted that the living-room and kitchen lights were on in the bungalow, experienced a fleeting sense of guilt. Like the times he used to come and stay when he was a teenager and he'd been to a disco at the hall which did not finish until the early-hours. And a fatigued Aunt Elsie was waiting up for him. You know I can't possibly go to sleep until you're safe back, John. Emotional blackmail.

He pushed open the gate and his booted feet crunched on the gravel. Next door was in darkness and their car wasn't parked outside where it usually was. Probably they had done what quite a lot of the residents had done, fled Stainforth until it was all over. You couldn't blame anybody for that. John wished there was somewhere his aunt could go in the meantime but he knew only too well that no way would Aunt Elsie be persuaded to vacate her home, not even in the threat of a nuclear war. 'This is the place I'll die in, John,' she had told him some time ago. 'The only time I'll leave here is when they carry me out feet first.'

He slowed his step, saw the light shafting out through the partly open back door. Now that was naughty of her, hadn't he reminded her before he left that morning to keep all doors and windows shut?

He pushed open the door, saw the empty kitchen, a plate and cup on the draining board. Silence except for the hum of the fridge. Even those over-sweet commercial shandies would be welcome right now.

'Aunt Elsie,' he called. 'I'm back.'

No answer. Still, she was becoming a trifle hard of hearing even if she refused to admit it. She was probably asleep in the armchair in the other room. I didn't hear you come in, John. What time is it?

The clock on the cooker read 10.20. He strode to the door which led through to the living-room; that was open a few inches too. He flung it wide and stood aghast, petrified at the scene which greeted him, his brain struggling to accept what his eyes saw.

The old lady was dead, there was no doubt about that. She lay face downwards on the carpet, her white hair having flipped out of that bun, spraying across her head and shoulders in the manner of a shroud which tried to hide the corpse it covered. The grandfather clock ticked loudly, steadily. Mournfully.

Even as his brain registered shock, he saw the snake. It was on the mat only a few inches from his feet, a long length of serpent that did not move, just saw and was afraid because it had wandered out of its own environment into the domain of Man.

John Price did not hesitate. He stooped and with one lightning movement he grabbed it just below the head, scooped it up and held it out at arm's length, felt its futile struggles begin, its helpless wriggles.

'You bastard,' he hissed, 'of all the land you've got to roam in peace you have to come in here and kill an old lady.'

Swiftly he carried it across the kitchen to the open back door and with one deft movement he hurled it out into the night, watched the shadows swallow up the four-foot-long thrashing creature, heard it thud softly on to the lawn.

He stood there in the doorway, trembling and feeling slightly sick. Then he came to a decision and with feet that dragged he began to retrace his steps down the main street and into the village.

They were still drinking in the Rising Sun. Nobody could blame them for that but when you had a personal tragedy you instinctively resented the way life went on without so much as a hiccup. Only a few lights showed in the houses now. Bed was a good place to be and in your own house with the doors locked you felt safe. You kept your feet under the sheets even on a hot night because that way nothing could come up from under the bed and entwine your ankle, slither up you and bite you.

'You still around!' there was sarcasm and resentment in PC Aylott's voice as John Price entered the office.

The constable was checking out a sheet of 'snake sightings'. Ten of them, inevitable but all figments of the imagination. Maybe some of them were hoaxes but they all had to be checked out. There was a minority of the general public that was a bloody nuisance when any major crisis cropped up. Sensation seekers, downright bloody liars and a sprinkling of idiots who over-reacted.

'Elsie Harrison's dead.' John thought his voice seemed to come from somewhere a long way away. A whisper that echoed, mocked. Dead . . . dead . . . dead.

The policeman's expression altered, his pale blue eyes narrowing, thin lips barking one word, a question. 'How?'