She saw DS Carter, the silver-haired man who had sat at the briefing, walking down the steps from the pedestrian bridge above, chatting with well-rehearsed ease to a much younger woman whose ebony hair was tied in a pony tail. A slim white man in a baseball cap, blue jacket and carrying a red holdall stepped in front of Gabriel and Bose, compelling them to slow down. They walked behind the man, Gabriel forcing herself to look disinterested and bored as she took in every detail of every face in the crowd around her.

Gabriel had been to St Pancras station only three or four times since it had been turned into London’s rail link to mainland Europe, and each time she was amazed how much this tatty old station had been transformed. Gone were the tired platforms, grimy Victorian arches and the decades of neglect – in their place was clean red brick, wooden floors and steel walkways. There was a cockiness about the place, an echo of the swagger of the Victorian engineers who put up this vast cathedral to the industrial age in iron, brick and glass.

The man in the baseball cap drew her eyes. There was something about his walk that dragged her thoughts back into the moment. He was limping, but that wasn’t it. Was it one of her team maybe? And then he half-turned to the display boards above their head that indicated platforms for the next few trains. Gabriel watched as if in slow motion as his profile came into focus just five or six feet away. A sharp nose poking out from the dark glasses. A length of red beard. A haggard cheek.

And then, two years of anger, of frustration, of disbelief swept through her. Abu Mujahid? Her hand reached for her pocket and pulled out her phone. He hadn’t seen her. He didn’t know she was there. Maybe he wouldn’t recognise her. She needed to attract the attention of the spotter with them, who had stepped into an organic snack bar to their right and was out of sight. She stopped, suddenly, and Bose collided into her.

‘Sorry, ma’am,’ Bose said, too loud and far too much like a police officer. The man turned and stared. And as he did, there was no doubt. It was Abu Mujahid. His cool eyes looked straight at Gabriel – boring through her skull into her brain. For a moment, for the tiniest fraction of a second, as a flicker of recognition passed across his face, the universe came to a stop. There was no sound. No movement. No people. No air. Just the two of them. Gabriel felt she could hear his heartbeat, the sound of his blinking and the rustle of his shirt.

‘Shit,’ said Bose, breaking the spell. The world turned back to normal and the sounds of the station filled Gabriel’s ears once more. Abu Mujahid flicked his head around and launched himself into a limping run away from them and towards a row of shops in the centre of the station.