‘The summer of 2016, Isobel Le Marchant is in final reach of her goal. Director General of MI5. Icing on the cake, she becomes a Dame. Route to the top – her brilliant handling of the operation which has made Britain safe. Imagine her peddling it. In the eleven years after 7/7, the Islamist threat in the UK is nullified, plots intercepted, arrests made, jihadists disappear to the Middle East never to return. But Kareem has served his purpose. She’s arrived. And only she and he know what he’s been doing to get her there. Maybe only he knows where the bodies are buried. The one potential loose cannon out there who can now threaten her. The skeleton in the cupboard. The darkness in the soul.’

‘I’m listening.’

‘That drone strike’s not a cock-up or own goal. She’s in on it. Knows precisely who’s in that car. She’s the one who’s celebrating.’

‘Is she capable of doing that? To a man she loved.’

‘Come on,’ he said, ‘she’s Director General of MI5. She’s no softie. There’s another angle. She knows jihad in the UK is changing. Lone wolves, single nutters, technology available to all. The Kareem gambit is out of time. Its success relies on there being networks, or parts of networks – however small – that can deliver him the so-called “traitors”. Or the future “martyrs” to be vetted and tested. Kareem has no access to lone wolves. His usefulness is dwindling. She’s squeezed him dry.’ He hesitated, unsure how Sara was taking it. ‘Maybe those long legs squeezed him dry too.’

‘She has emotions,’ protested Sara. ‘I saw them. There were suppressed tears in her eyes.’

‘Crocodile tears.’

‘Even if you’re right – even if she felt she had to do it – she still would have mourned him.’

‘OK, maybe. But like the dramatist, we sometimes have to kill our darlings.’

He walked over to the window. A concrete lorry passed below, carrying the foundations for another addition to the jungle of affluence. ‘It doesn’t matter,’ he said, eyes glazing over the sprawl of buildings growing, it seemed, photosynthetically towards the late-morning sun. ‘How? Why? It really doesn’t matter. She’s the boss, he’s dead and all we have are a few files we’re told are the tip of an iceberg and an arrangement between the state and a probable socio or psychopath that I once signed my name to.’

She walked over to him. Only now did she fully see the guilt that had stuck. ‘It’s not your fault. You didn’t have a choice.’

‘We all have choices, Sara. They make us who we are.’