‘Depends how much money you’ve got,’ Ken said. ‘If you’re a big spender, you can get a speedboat from Dunkirk to Dover for twelve grand. But if money’s tight, you can buy a passage to England for as little as a hundred quid in Calais. They sell it as a guaranteed entry on social media – and these traffickers have hundreds of accounts online – but really that hundred quid just buys you one attempt to squat in the back of a lorry heading for Dover. Not that they confine themselves to the south coast these days. As security tightens up around Dover the smugglers’ speedboats are heading for Portsmouth, Whitstable, Tilbury, Hull – you name it. And if they make it, most of them can stay forever. Nobody gets shipped back to a war zone.’ He indicated the passports. ‘I’ll tell you something about these girls.’

I stared at the solemn beauty of Hana Novak’s passport photo.

‘What’s that?’ I said.

He sighed. ‘They were unlucky,’ he said.

‘I’ve found the lorry,’ Billy Greene said, excitedly swivelling in his chair. ‘Got it on ANPR.’

Automatic Number Plate Recognition is the system we use for storing registration numbers, even for vehicles that we are not looking for at the time. Around eight thousand ANPR cameras photograph over thirty million numbers every day, and the details are stored for two years.

‘The lorry is a five-ton refrigerated Sinotruk that was bought for cash at an auction in Kent last summer,’ Billy said. ‘It’s a Chinese make, although the plates were Turkish. That’s what they do – the people smugglers – they pick the rides up for cash at auction. Makes it as hard to trace as a pay-as-you-go phone.’ He turned in his chair to peer at his screen. ‘It entered the UK yesterday on the last ferry from Dunkirk. Landed at Dover.’

‘Any CCTV of the driver?’ Whitestone asked.

‘I’m still looking, ma’am,’ Billy said.

‘So we’re assuming the owner of the thirteenth passport wasn’t driving?’ I said.

‘It’s unlikely,’ Whitestone said. ‘Because the owner of the thirteenth passport is a woman and the drivers who smuggle in illegals are all men. At least, that’s how it has been until now. It’s not an equal opportunities profession. Find the thirteenth woman and then you find the driver. Find the driver and you find the scumbags who run the whole stinking operation.’

‘Why did the driver do a runner?’ Edie said.

‘Perhaps he looked in the back, realised the women were dying or already dead, and panicked,’ I said. ‘Perhaps he didn’t get paid. Perhaps there was nobody there to meet him.’

‘But why was it below freezing in the back?’ Edie said. ‘He smuggled a lorryload of girls into the country and then froze them to death. It makes no sense.’