‘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 Yo-less. ‘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 Yo-less. ‘Being Little Black Sambo isn’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 Yo-less, 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 Yo-less.

‘Right,’ said Kirsty. ‘It’ll be just like the man who trod on Yo-less’s dinosaur.’

‘It may have been some sort of insect, now I come to think of it,’ said Yo-less. ‘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.