The second booth was clear. Then the third. Barker signalled back to Carter, who advanced, handgun raised.

Barker walked towards the next booth; Gabriel followed a couple of metres in her wake. She knew that was against protocol. She knew she should give Barker space to do her job. But right now, she didn’t care.

Barker paused for a second, glanced around the restaurant to locate Carter and then stepped in front of the fourth booth. Abu Mujahid was crouched in the corner, his knife held against the neck of a young man – aged maybe seventeen – whose pointed face was too pale and whose eyes were wide with terror. Two boys, perhaps a little younger, were frozen in their seats opposite. More innocents, thought Gabriel.

‘Drop the knife. Now.’ Barker’s voice was clear and commanding.

Gabriel moved closer. Abu Mujahid wore a tight white T-shirt under his anorak and blue jacket – tight enough to show he was not wearing an explosive vest.

‘Jack – put the knife down.’ The words left Gabriel’s mouth before she realised she had spoken. Abu Mujahid stared at her, but this time there was no moment of stillness. He was shaking, breathing hard, and his face was flushed.

‘Final warning. Put down the knife,’ said Barker as she levelled her gun at Abu Mujahid’s expressionless face, two metres away.

At that, Abu Mujahid turned his face to look at Gabriel. Was it her imagination or was there a flicker of amusement on his face?

‘Let me walk out of here, or the kid dies.’ Abu Mujahid’s voice was unwavering. ‘Or do you want another life on your hands?’

Gabriel looked again at the young man’s eyes. They were brown. Like Isobel Harris’s eyes.

Carter was standing behind her to her left, Barker was in front to her right. Neither had a clear shot, no chance of avoiding the young man.

‘Another kid in the firing line then, Jack?’ said Gabriel, struggling to keep her voice steady. ‘That’s usually your style, isn’t it? Sacrificing children to save your own life? The ones who can’t fight back? Or old ladies maybe.’

Abu Mujahid’s grey eyes glittered coldly across the booth. He didn’t move.

‘I wondered how you live with yourself, Jack? I mean, I’m sure you’ve come up with some justification for murdering Isobel Harris. And the Muslims in Syria who did not support your cause, and the women and girls you used as sexual slaves and who you raped. I’m sure you’ve come up with a way that helps you to sleep at night. But I notice you’re still alive, Jack? You’ve not opted for martyrdom? Are you a coward, Jack? It kind of looks like it from here.’

Again, no movement. What are you doing, Sophie? The voice in her head was panicky and fast. The teenager in Abu Mujahid’s grip was staring at her, unbelieving.

‘Does it annoy you, Jack, that you’ve been caught by a copper? And a woman at that? You’re not so keen on women, are you, Jack? Not so keen on me? Tell you something for nothing. The feeling’s mutual, Jack.’