And that was it. I waited for something more but it never came. And I saw that something had changed in DCI Whitestone after her son had been attacked in a bar last summer. The assault had left her teenage boy blind and Whitestone had understandably been a mess of rage and grief. But now that anger had cooled into something hard and unforgiving that I had never seen in her before. Something had calcified in the heart of Pat Whitestone.

Because of what happened to her son, because of the boy’s bad luck in being in the wrong place with the wrong people, because of the random madness of some little pound-store gangster putting a glass bottle across his eyes in some dismal little club on the Liverpool Road.

‘I think Edie needs to take it easy,’ I said.

Whitestone looked at me sharply.

‘I think we need to find whoever put those women in that refrigerated lorry,’ she said. ‘And we need to do it now. Before they do it again. What’s the story with this bunch of anarchists, Imagine?’

‘Imagine are meant to be some kind of no-borders, imagine-no-possessions radicals. Troy – the leader – the one with the tattooed face – has about as much human compassion as a merchant banker, as far as I can see. We had to pay for the privilege of handing out coats.’

‘So these hippies – radicals – whatever they are – are they for real or not?’

‘Imagine run the camp in Dunkirk. And Troy runs Imagine. He rules that camp like a feudal chief. It may be a dungheap, but it’s Troy’s dungheap. And they certainly do a little freelance trafficking when they’re not saving the world.’

‘These are the photos on Draganov’s personal phone,’ Billy said.

He had rigged the smartphone to his workstation. A photograph appeared on the big screen. A man and a woman standing side by side, the man’s scarred face smiling, the woman – thin, maybe early twenties, pretty in an exhausted sort of way – totally impassive. The man was Zlatko Draganov.

‘We’ve seen her before,’ Whitestone said. ‘Her face was in the stack of passports we found in the cab. One of the Turkish passports.’

‘There were two Turkish passports,’ Billy said. ‘One in maroon – the standard Turkish passport – and one in green – which allows the bearer to travel visa-free to some countries. In the opinion of Ken, our Questioned Documents guy from Heathrow, both of those passports were false. But the young woman pictured here had the higher-status green passport, travelling in the name of Rabia Demir. But who knows what her real name might be?’

There was some kind of modest castle in the background, carefully maintained, its pale walls topped with red-brick parapets.