‘It’s important,’ he was saying, ‘to baseline why we’re doing this. Operation Methuen is a Tier One national priority. We are reacting well past our comfort zone here. You’ll all be working your cases hard to generate penetrative insight into this network’s mindset and physical locations. And you’re not alone,’ the controller continued. ‘The Met are working with us on this from the get-go to find the best evidential package that will deliver successful prosecutions. And let’s not forget the lawyers.’ That’ll be the day, Luke thought. ‘Our legal advisers will be keeping a careful eye on our ethical obligations to our agents throughout this case. I realize some of the people you’ll be dealing with are, to put it mildly, somewhat unsavoury, but we still have a duty of care to them.’

The controller looked up towards the ceiling and closed his eyes, as if remembering a past operation that had not gone to plan. ‘We all know,’ he said, looking back at the room again, ‘that agent reporting can generate intelligence we can’t get through technical means. Only an agent can reveal the attack planning that’s not visible through surveillance. But that doesn’t mean …’ he stopped and made a theatrical gesture with his hand towards the frosted glass panes ‘… that we can simply throw our agents’ rights out of the window when it suits us. Now … I’m going to leave you to talk through your cases with your OPSYs. We meet back here at five.’

Luke scanned the room. He hadn’t yet met his operational security adviser. The person who sits outside the official hierarchy of an investigation so he or she can focus on the security of the agent and the public. ‘Have a think,’ someone had once said to Luke, ‘what it would mean for your agent if everyone in your target network got arrested except for him. Their cover would be totally blown, wouldn’t it? You’d have to rehouse him or her and then you’ve lost your source. So your OPSY is there to stop you making a mistake like that.’

Luke spotted her as she made her way over to him. Young, early thirties, with a nose ring.

‘Luke? Michaela Norton.’ She flashed him a smile as she introduced herself. Was there a slight trace of a northern accent?

‘I’m afraid you might have drawn the short straw here,’ Luke said.

‘And why’s that?’

‘Well, I work across the river, which I’m sure you know, so … my agent isn’t in this country, he’s overseas.’