The streets Lil knew, the terraced house where she grew up, the shops and the school and the people – it was as if none of it had ever existed. It took us two hours to find her.

‘There she is,’ Edie said.

Lil was standing outside a brand-new block of apartments, talking to a porter in a dark suit with the tribal markings of West Africa on his face.

‘I’m looking for Harry,’ Lil explained.

‘Harry’s not here,’ he said. ‘Is no Harry. Please go.’

Edie took her grandmother’s arm, laughing.

‘Come on, Nan, let’s go home. Went for another wander, didn’t you?’

Lil looked confused.

‘Molly?’

‘It’s Edie. Your granddaughter. Remember?’

‘Edie. Yes. Of course. That’s quite right. Edie. I knew that.’

A dog walker emerged with half a dozen dogs. She looked askance at Lil.

‘Excuse me,’ the old lady said to the dog walker. ‘Have you seen Harry? He’s – what? – must be sixteen by now.’

The dog walker moved quickly away.

The porter had his arms spread wide, ushering us out. Edie put her small body between the porter and her nan.

‘We’re going, pal,’ she said very quietly. ‘But don’t rush us.’

She gently led Lil to the street, holding her close, softly whispering to her.

‘Harry’s gone, Nan. Remember now? Harry went a long time ago. Harry was your brother, wasn’t he?’

Lil became suddenly tearful.

I stared at the street. Building work was happening everywhere. The cranes loomed over the city as if they were the masters now. On the far side of the street a queue of men were being given hard hats and hi-vis jackets.

And that was when I saw Nesha Novak.

He was carrying bricks in a wheelbarrow. Almost running with them, as if it was some kind of grim new sport. I gave Edie the keys to the BMW and told her I would meet her at the car.

Hana Novak’s kid brother looked at me as I brushed past the queue of men. But he carried on working, racing his load to the massive hole that was the centre of the site. Now that London was close to capacity, most of the building work was going underground.

Russian voices were everywhere. Men with shaven heads, cigarettes jammed between their lips and, among all the ragged sportswear, there were hoodies that looked as though they had been bought from a tourist shop on Oxford Street. There were more Union Jacks than the Last Night of the Proms.

I found the foreman.

‘See that kid with the wheelbarrow?’

‘What about him?’

‘He’s sixteen.’

‘So what?’

‘He’s in this country illegally.’

The foreman smiled. He said something in Russian to his mates. Everybody had a good old chuckle.

‘So what?’ he repeated.

I took out my warrant card and showed it to him.