I took out my phone and called up the photograph of Hana and Nenad Novak. I put my thumb and index finger on the screen and slid them apart so that their smiling young faces disappeared and all that remained was the enlarged image of the scar-faced man in the background.

‘I never saw him,’ Hill said. ‘But I bet I can find him.’

He sounded far more convinced than when I had first showed him the image.

‘Listen – it’s not a big world once you get to the French ports,’ he said. ‘The world – that world – narrows right down by the time you get that close to England. Those refugee camps – they’re not cities. They’re villages. Reeking, stinking villages. You can’t hide in a village.’

‘So how does it work?’ Whitestone said quietly.

‘There’s a lorry park in Saint-Omer,’ Hill said. ‘It’s a long way from the migrant camp at Dunkirk – thirty miles or so inland. The clients have already paid the carriers in advance by the time they arrive at the lorry park. They pay by money transfer, Western Union or the like. Once the cash has been collected this side, the clients get the green light to travel. And once everybody’s boarded, it’s forty minutes to the ferry and on to the UK.’

‘Loving these euphemisms,’ Whitestone said. ‘You never go to the camps for your clients?’

‘Too dangerous,’ he said. ‘Too many knives. Too many headcases that have just walked all the way from a war zone. Too many child soldiers. Too many mad blokes with full beards and empty eyes.’

‘Tell us about your employers,’ I said. ‘Tell us about Imagine.’

‘Never worked for them before. I told you. Bunch of nutters. Idealists. Anarchists. They want national borders down and the Third World moving into the Home Counties for the good of humanity. Don’t hold your breath, far as I’m concerned. But there are all sorts down there. You’ve got your radicals like Imagine who want people to come in for political reasons. You’ve got your pimps, your returning Jihadis, your career gangsters. You’ve got people who just want to bring dear old granny in from Kabul or Damascus or Aleppo so she can enjoy the December of her years in Birmingham or Luton or Leeds. You’ve got economic migrants and you’ve even got some poor bastards who just want to avoid having their families blown to bits. Takes all sorts, eh?’

‘So the pick-up point is always at this lorry park in Saint-Omer?’ I said.