‘I’ll have … well, I’ll have everything,’ said Yo-less.

‘Me too,’ said Bigmac.

‘Cheeseburger?’ said Johnny.

‘Chilli beanburger,’ said Kirsty. ‘And I want to know what’s going on, OK?’

Sir John beamed at her in a slightly distracting way. Then he nodded at the waitress.

‘Make me one with everything,’ he said, slowly and carefully, as if quoting something he’d heard a long time ago, ‘because I want to become a Muslim.’

‘A Buddhist,’ said Yo-less, without thinking. ‘You always muck up the punchl—’ Then his mouth dropped open.

‘Do I?’ said Wobbler.

‘Well … I hung around for a while and you didn’t come back,’ said Wobbler. ‘And then—’

‘But we did! I mean, we will!’ said Kirsty.

‘This is where it gets difficult,’ said Wobbler, patiently. ‘Johnny knows. Supposing you didn’t go back? Supposing you were scared to, or you found that you couldn’t? The possibility exists, and that means the future forks off in two different ways. In one you went back, in one you didn’t. Now you’ve ended up in the future where you didn’t go back. I’ve been here since 1941. Don’t try to think too hard about this, because it’ll make your brain hurt.

‘Anyway … first I stayed with Mr and Mrs Seeley,’ he continued. ‘I’d met them that first day. Their son was away in the Navy and everyone thought I was an evacuee who was a bit daft and, what with one thing and another, there’s too much to worry about in a big war for people to ask too many questions about one fat boy. They were very nice people. They sort of … adopted me, I suppose, because their son got torpedoed. But I moved away after a few years.’

‘Why?’ said Kirsty.

‘I didn’t want to meet my own parents or anything like that,’ said Wobbler. He still seemed out of breath. ‘History is full of patches as it is, without causing any more trouble, eh? Changing my name wasn’t hard, either. In a war … well, records go missing, people get killed, everything gets shaken up. A person can duck down and pop up somewhere else as someone else. I was in the Army for a few years, after the war.’

‘You?’ said Bigmac.

‘Oh, everyone had to be. National Service, it was called. Out in Berlin. And then I came back and had to make a living. Would you like another milkshake? I personally wouldn’t, if I were you. I know how they’re made.’

‘You could’ve invented computers!’ said Bigmac.

‘Really? You think so?’ The old man laughed. ‘Who’d have listened to a boy who hadn’t even been to university? Besides … well, look at this …’

He picked up a plastic fork and tapped it on the table.

‘See this?’ he said. ‘We throw away millions of them every day. After five minutes’ use they’re in the trash, right?’

‘Yes, of course,’ said Kirsty. Behind Wobbler, the staff were watching nervously, like monks in some quiet monastery somewhere who’ve just had St Peter drop in for tea.