The cafe he had chosen was in Farringdon, and they took a shortcut through the deserted Smithfield Market to get there. It always reminded Porter of an upturned ship’s hull, blue and white girders curving overhead. It was deserted at this time of day apart from a few others cutting through. Turn up after 8 a.m. and you’d missed the party. Ironic that meat was still sliced and diced today, on the same spot that saw the likes of William Wallace executed centuries ago. Porter wondered what Wallace would make of the tourists taking selfies outside, angling their cameras upwards to catch the sculptures of the dragons that guarded the entrance.

When they arrived, Gavin Locke was already there. It wasn’t hard to spot him; he was hunched over a large coffee cup, both hands encircling it and his index fingers tapping out a nervous beat either side of the handle. His hair looked like it had been combed with a branch, and his waxy pale face made him look ten years too old. He wore a dark grey suit with the faintest of pinstripes running through it, and a conservative dark blue tie with no pattern. The combination of average urban office-wear and clean-shaven face was the uniform of countless city jobs. He stood up when they approached.

‘Mr Locke?’

‘Yes, that’s me.’ Locke gave a nervous smile, his eyes flitting between the two of them.

Porter took the hand that Locke held out, and noted the clammy palm that met his. They introduced themselves and pulled out a chair each.

‘Can I get you a drink?’ he asked.

‘No, thank you, Mr Locke,’ said Porter.

Locke resumed the cradling of his cup. ‘So you want to talk about Natasha,’ he said. It was a statement, not a question.

Porter nodded. ‘We need to speak to her, Mr Locke, and we’re hoping you can point us in the right direction. It doesn’t appear that she’s been home to her flat in some time. When was the last time you spoke to her?’

‘My mum didn’t tell you?’ he asked.

Porter and Styles looked at each other, both noting the significance of the question. When Styles had called him there had been no mention of the fact they’d spoken to Mary Locke, or that she was the one who had given them his number. That meant she had indeed called him, and in all likelihood the call had been made as soon as they had left her house.

‘She didn’t think you’d had any recent contact with her but said we should ask you the question.’

‘I’ve not seen her since her twenty-first birthday.’ His eyes fixed on the dregs of coffee that lurked in the bottom of his cup as he spoke. ‘I was only six years old. It was that long ago I can’t even remember what the last thing she said to me was.’