"spy spy spy," said the boy.

"Oh, shut up."

"An" you wobble. I saw that Goering on the newsreels. You look jus" like him. An" you're dressed up all funny. Spy spy spy!"

Wobbler sighed. He was fairly used to this, only not so much these days because once he'd just been fat and now he was big and fat.

"And you're stupid," he said. "But at least I could get slimmer."

Biting sarcasm didn't work.

"Spy spy spy! Nasty nasty Nazi!"

Wobbler tried walking faster.

"I'm goin" to tell Mrs Density an" she can telephone our Ron and he can come an" arrest you!" shouted the boy, jumping along behind him.

Wobbler tried walking faster still.

"He's got a gun, our Ron."

A man went by slowly on his bike.

"He's a spy," said the boy, pointing at Wobbler. "I'm arresting him for our Ron."

The man just grinned at Wobbler and pedalled onwards.

"Our Ron says you spies send Morse code messages to Nazi submarines by flashing torches," said the boy.

"We're twenty miles from the sea," said Wobbler, who'd almost broken into a run.

"You could stand on something high. Nyer nyer nyer. Spy spy spy."

It was just plain stupid, thought Bigmac, as he watched the two plumes of steam in front of him.

What kind of idiots built a car without power steering or synchromesh gears and put in brakes apparently operated by string? He was practically doing the world a favour by taking the car off the road.

Not just off the road, in fact, but over the pavement and across a flowerbed and into the Alderman Bowler Memorial Horsetrough.

The plumes of steam were quite pretty, really. There were little rainbows in them.

"Well, now," said a voice, as someone opened a car door, "what do we have here?"

"I think I banged my head," said Bigmac.

A large hand encircled his arm and pulled him out of the car. Bigmac looked up into two round faces that had "policeman" written all over them. There was room for quite a lot of things to be written all over them. They were very large faces.

"That is Dr Roberts" car," they said, "and you, my lad, are in for it. What's your name?"

"Simon Wrigley," mumbled Bigmac. "Ms Partridge knows all about me ... "

"She does, does she? And who's she?"

Bigmac blinked at the two faces which miraculously flowed together and became one.

He'd quite liked Ms Partridge. She was nasty. The two social workers he'd had before had made out that he was wet, whereas Ms Partridge made it clear that if she had her way Bigmac would have been strangled at birth. You could respect someone like that. They didn't make you feel like some kind of a useless nerd.

Something prodded at his memory.

"When is this?" he said, rubbing his head.

"You can start by telling me where you live-" The policeman leaned closer. There was something about Bigmac that bothered him.

"What do you mean, when is this?" he said.

"What year?"

The policeman had fairly fixed ideas about what should happen to car thieves, but they usually knew what year it was.

"It's 1941," he said, and straightened up. His eyes narrowed.

"Who's the captain of the England cricket team?" he said.

Bigmac blinked.

"What? How should I know?"

"Who won the Boat Race last year?"

"What boat race?"

The policeman looked again.

"And what's that on your belt?"

Bigmac blinked again, and looked down.

"I didn't nick it," he said quickly. "It's only a transistor, anyway."

"What's that wire going into your ear?"

"Don't be daft. It's only the earphone-"

The policeman's hand landed on his shoulder with the kind of thud that suggested it wasn't going to let go in a hurry.

"You come along with me, Fritz," he said. "I wasn't born yesterday."

Bigmac's brain drifted into focus. He looked at the uniform, and at the crowd behind it, and it began to dawn on him that he was all alone and a long, long way from home.

"I wasn't born yesterday, either," he said. "Does that help?"

Johnny, Kirsty and Yoless sat in a little garden. As far as Johnny could tell, it was where part of the ring road and a traffic island were going to be one day. Now it contained a bench and some geraniums.

"They'll blow up Paradise Street tonight," said Johnny.

"Where's that?" said Yoless.

"Here. It's where the sports centre was ... will be, I mean."

"Never heard of it."

"Yes. I did say. It got blown up. And you know the funny thing about it?"

"There's something funny about it?" said Kirsty.

"It was by accident! The Germans had meant to bomb the big goods yard at Slate! But they got a bit lost and the weather turned bad and they saw the railway yards here and dropped all their bombs and went home. Everyone was in bed because the air raid sirens didn't go off in time!"

"All right, all right, I know, you've told me before, and all about Adolf and Stalin. It's very sad but you shouldn't get worked up about it," said Kirsty. "It's history. That sort of thing happens in history."

"Aren't you listening? It hasn't happened yet. This is now. It's going to happen tonight."

They stared at the geraniums.

"Why haven't we gone back yet?" said Kirsty. "We've been here ages."

"How should I know?" said Johnny. "Maybe the further you go, the longer you stay."

"And we just happened to go to somewhere you know all about," said Yoless. "That's a bit strange, in my opinion."

It had worried Johnny, too. Everything felt real, but maybe he'd just gone mad and taken everyone else with him.

"I don't want to stay here, that's definite," said Yoless. "Being Little Black Sambo wasn't my idea of a full life."

Johnny stood up and grasped the handles of the trolley.

"I'm going to see Paradise Street," he said.

"That's a very bad idea," said Kirsty. "I told you, anything you do affects the future."

"I'm only going to have a look."

"Oh yes? I find that very hard to believe, actually."

"She's right," said Yoless, trying to keep up. "You shouldn't mess around with Time. I read this book where a man went right back in time and trod on ... on a dinosaur, and changed the whole future."

"A dinosaur?" said Kirsty.

"I think it was a dinosaur. Maybe they had small ones."

"Huh. Or he was a very big man, perhaps," said Kirsty.

The trolley bumped off the pavement, rattled across a road, and clanked up the pavement on the other side.

"What're you going to do?" said Kirsty. "Knock on people's doors and say, "Excuse me, some bombers are going to bomb this street tonight."?

"Why not?"

"Because they'll lock you up, that's why," said Yoless.

Right," said Kirsty. "It'll be just like the man who trod on Yoless's dinosaur."

"It may have been some sort of insect, now I come to think of it," said Yoless. "Anyway, there's nothing you can do. It's already happened, otherwise how come you know about it? You can't mess up history." The trolley stopped so quickly that they ran into the back of Johnny.

"Why does everyone always talk like that?" he said. "It's stupid. You would really watch someone run over by a car because that's what was supposed to happen, would you? Everything we do changes the future, all the time. So we ought to do what's right."

"Don't shout, people are looking at us," said Kirsty.

The trolley bumped over the kerb and started to bounce on some cobbles. They were already out of the town centre.

And there was Paradise Street.

It wasn't very long. There were only ten terraced houses on either side, and some of them were boarded up. The far end was a pair of double wooden gates to a factory. They'd once been painted green, but time and the weather had turned the colour into a sort of mossy grey.

Someone had chalked a set of goalposts on the doors, and half a dozen small boys in knee-length shorts were kicking a ball about.

Johnny watched them as they scuffled and perpetrated fouls that would have gladdened the heart of any football manager.

About halfway along the street a young man was repairing a motorcycle. Tools lay on a piece of sacking on the pavement. The football emerged from a complicated tackle, hit the spanners, and almost knocked the bike over.

"Turn it up, you little devils," said the man, pushing the ball away.

"You never said anything about children," said Kirsty, so quietly that Johnny nearly didn't hear her. Johnny shrugged.

"It's all going to get blown up?" said Yoless.

Johnny nodded.

"There wasn't very much detail in the local paper," he said. "They didn't used to put very much in, in case the enemy read it. It was all to do with something they called the war effort. You know ... not wanting to let the enemy know you'd been hurt. There was a photo of a lady with her thumb up saying "Blackbury can take it, Mister Hitler!" but there was hardly anything else about the raid until a couple of years afterwards."

"You mean the government hushed it up?" said Kirsty.

"Makes sense, I suppose," said Yoless gloomily. "I mean, you don't want to say to the enemy, "Hey, you missed your target, have another go"."

The football slammed against the factory gates, rattling them. There didn't seem to be any teams. The ball just went everywhere, surrounded by a mob of small boys.

"I don't see what we could do," said Kirsty. Her voice sounded uneasy, now.

"What? Just now you were telling me I shouldn't do anything," said Johnny.

"It's different when you see people, isn't it?"

"Yes."

"I suppose it wouldn't work if we just told someone?"

"They'd say "how do you know?" and then you'd probably get shot as a spy," said Yoless. "They used to shoot spies."

Heavy Mental