He started as something flapped silently from a branch above his head and quickly disappeared into the fog. An owl. Another species which would suffer in the long run if it was deprived of these rodents which were its natural prey.

Professor Brian Newman and Susan Wylie returned from the Biological Research Centre just in time for the televised news at ten 'O'clock. A reporter was talking in one of the main Birmingham thoroughfares, with blackened skeletons of buildings all around him, people huddled into small groups, and some traffic filtering by at intervals. Gangs of workmen wearing protective headgear were engaged in clearing-up operations,

'The weeks of terror have finally come to an end;' the reporter was saying, 'and at last people are emerging from their homes, wondering if it really happened or whether it was all one hellish nightmare. But here is the proof of reality.' He indicated the wrecked city around him. 'Burnt out shops and office blocks, many collapsing and burying bodies beneath them. During today alone, sixteen corpses, beyond recognition, have been recovered from the ruins of New Street Station. The fighting is over, and the restrictions which have been in force throughout the Midlands were lifted today. Members of the British Volunteer Force are assisting in site clearance, and many civilians have joined in to help also. But the gladdening news is that the bats from hell, the disease-carrying creatures which have been responsible for the thousands killed and a state of near-anarchy in and around the city of Birmingham, are no more. And for that we have to thank Professor Brian Newman, whose' idea it was to import the latest weapon in warfare against rodents from the United States. This is a virus not unlike myxomatosis in rabbits, but much deadlier. Within a week of its initial release tens of thousands of bats, mice and rats have died in the 'Midlands, and we have just had reports of similar rat deaths as far a field as Manchester and Newcastle-on-Tyne. Whilst the killer disease travelled no further than a radius of fifty miles around Birmingham, this rodent plague appears to be spreading. We can only ask ourselves, what will Britain be like without the vermin against which we have been waging war for centuries? Even Professor Newman cannot forecast the long-term effects. Gerald Watson, News at Ten, Birmingham.'

Brian Newman leaned forward and switched off the television.

'Well,' Susan commented, 'you're no longer the villain of the piece. They're hailing you as a saviour.'

'And within a year the damage will have been restored, and the bats will be only a memory,' Newman muttered, 'but there are those who will never forget, those who lost loved ones. I can do nothing to ease their grief.'

'I'll go and make some supper.' Susan stood up and moved towards the kitchen. 'At least we needn't be afraid to go outside after dark now.'

Brian Newman picked up the evening paper and had hardly opened it up when a piercing scream came from the kitchen.

'Susan!' he yelled, scrambling to his feet, but before he reached the door Susan Wylie came rushing in, her face deathly white.

'Oh, God!'she sobbed.

'Whatever is it?' he demanded pulling her to him.

'Nothing, really.' She made an attempt to pull herself together, 'it was... only a... a mouse. When I opened the cupboard it rolled out on to me. Phew! After all the mice, rats and bats I've held these past weeks whilst you injected them, and then we get one in the kitchen and I nearly have hysterics. It's sort of... different in the lab, isn't it?'

He pulled her to one side, and went into the kitchen. The dead mouse lay on the floor by the sink-unit, its body bloated twice its normal size as though it had been blown up with a pump, the head pink and swollen, eyes buried beneath an unnatural growth, a bulbous matter-filled ball of cancerous, mangy fur.

'It... it's repulsive, isn't it?' Susan caught her breath. 'I... I never thought this disease was quite as terrible as that. Oh, it's horrible. And we've done that to millions of them!'

He pulled her gently back into the living-room and closed the door. Try not to think about it,' he said, kissing her. 'It's not a pretty sight, I know, and if I'd had any other choice I'd never have brought this vile disease over here. But it was the only way. It was either that or the end of civilisation as we know it.'

'I'm sorry.' She tried to smile. 'It was ... just, well, the way it roiled out of the cupboard on to me as though . . . as though it was trying to make one last attempt to get revenge.'

'I'll go and put it in the dustbin,' he said.

'No,' she insisted. 'I'll do it. I've got to get used to them. No doubt there'll be dozens more of the creatures lying about dead in the coming weeks. And I'm as much to blame for it as you. It was my fault that the bats' cage got knocked over and they escaped.'

During the next few days Professor Newman busied himself carrying out tests on several of the dead creatures which had been brought into the Research Centre.

'Even the Yanks don't really know the extent of this virus,' Haynes said. 'We jumped the gun a bit, even for them. They know what it does to a rodent, but not why. As far as they can tell it's harmless to humans and all other animals, but we've got to be sure.'

'Damn it,' Newman replied with a grin, 'There's enough, been handled so far. If it is harmful then we're really going to be in trouble.'

Towards the middle of the afternoon the professor happened to notice Susan wiping a flushed brow with the palm of her hand.

'Are you all right?' There was consternation on his face.

'It's nothing.' She smiled weakly. 'I feel a bit feverish. A slight headache. Maybe it's the sudden change in the weather.'

'A good downpour doesn't do that to you,' he insisted, and tested her pulse. It was racing. 'I'd say you've got the flu coming on. Now go on back home and get to bed. I'll be back by five.'

'If you insist.' There was gratitude in her voice.

'I do,' he said. 'Are you sure you're OK to drive?'

'1'11 be all right.' She walked towards the door, swaying slightly.

He watched her drive away, standing at the window until she was out of sight, and there was a worried expression on his face as he resumed work.

It was 5.20 when Brian Newman eventually arrived back at Chasetown. As he let himself in through the front door he sensed immediately that something was wrong. The bedroom door was open, and from the hall he could see the neatly made bed. It was empty.

'Susan!'

She was not in the living-room. He dashed into the kitchen. One second of shock, immobility, and then he was on his knees at her side.

'Susan!' he breathed. 'Oh, my God! What's wrong?'

She did not reply. Her eyes were closed, her cheeks flushed with fever, her skin wet with perspiration. He began to undo her clothing with trembling fingers.

Seconds later he was telephoning for a doctor. The two or three minutes during which it took him to contact Doctor Jenkinson were agonising.

'I'll be right round,' the doctor snapped after he had listened to the symptoms. 'Make her as comfortable as you can, but don't try to move her.'

Doctor Jenkinson was Jess than five minutes arriving. He remembered the Williams family. There had been many since. It was his greatest fear that it would begin all over again.

'It isn't the virus,' Newman told him as he showed him into the kitchen where Susan still lay motionless on the floor, a blanket covering the lower half of her body.

'No, it isn't that, certainly,' Jenkinson said after a brief examination, 'although what it is I haven't a clue, quite frankly. Look at her eyes, the way they're puffing up ...'

Brian Newman stared in horror. It was true. The closed lids appeared to be swelling outwards without opening, as though some horrific growth was propagating at an unbelievable rate inside the sockets.