‘But this is one of our own,’ I said. ‘The boy is the son of my DCI at West End Central.’

‘I know whose son he is,’ said the DI from New Scotland Yard, the first frost coming into his voice. ‘But the boy didn’t see who glassed him – or so he says. And nobody in the club knows who did it – or so they say. There’s not a lot we can do.’ Now there was even more frost. ‘And if it was West End Central running the investigation – there’s bugger all you’d be able to do.’

I stared out the window. The dome of St Paul’s bone-white in the moonlight, the party people rolling down Charterhouse Street, the lights of the meat market coming on for the long night shift.

‘I know you did your best,’ I said. ‘It’s just hard to believe that nobody gets lifted for such a serious assault.’

The DI softened.

‘It’s rotten, I know. But even if we lifted one of these little gangsters from the Dog Town Boys, it’s not going to make the kid see again, is it? What can you do, eh? Sometimes the guilty just walk away.’

‘And there was never a lead?’

I heard him hesitate. ‘There was a girl. A young woman. From Hungary. Worked in one of those big Islington squares looking after kiddies of people who work in the City. A nanny. A nice Islington nanny called – let’s see – Margit Mester. Twenty-two. Lovely girl. When we went in that first night, stopped them all leaving and tried to have a word, I spoke to Margit Mester and she pointed out a local lad called Trey N’Dou.’

He spelled it for me.

‘You know this Trey?’ I said.

‘Yeah, Trey N’Dou is the leader of the Dog Town Boys.’

I let that sink in. ‘So what happened to your Hungarian witness, Margit Mester?’

I could already guess the answer.

‘We brought her in for a line-up that included Trey and she didn’t recognise him. Couldn’t place him at the scene. It was noisy, confusing, upsetting. The usual bullshit when a witness gets cold feet.’

‘Can I talk to Margit Mester?’

‘If you go to Budapest.’

‘She went home?’

‘Couldn’t get there fast enough when she twigged who she was pointing a finger at.’

Jackson came out of his room and crossed the loft. At the door, he raised his hand in salute and gave me his gap-toothed grin and pointed at the market. He was off to work. I lifted my hand – goodbye – and he slipped out.