‘No, don’t worry. And don’t stay late . . .’ Kate got a few paces down the corridor before she had second thoughts and went back. If Suzy was determined to staple herself to her desk, they might as well make it count. ‘Actually, it would be useful if you could do a briefing note on the Night Wolves for the foreign secretary and the PM, their links with the Kremlin and the GRU, their role in Ukraine, that sort of thing.’

Suzy looked pleased. ‘Thanks,’ she said. ‘I really appreciate that.’

‘There’s a Cobra meeting first thing. I’ll give it to the PM and the foreign secretary there.’

Suzy’s smile broadened. Kate had already worked out that nothing pleased her new deputy quite as much as the prospect of catching the eye of their superiors.

4

KATE CHANGED INTO her trainers by the lift and walked out into the chill night. The wind was biting, so she took a cashmere beanie from her coat and pulled it down tight over her ears. Normally, this daily walk helped bring some order to her thoughts, but tonight, the rhythmic pace of the journey seemed to accelerate the rising tide of her anxiety. Now that Stuart had gone, the only person she shared her true state of mind with was her aunt Rose, who combined the role of mentor at work – as the long-time head of the Finance Department, it had been she who’d first encouraged Kate to apply for the Service from Cambridge – and surrogate mother at home. Kate’s real mother was in a home nearby with Alzheimer’s, which was a relief to everyone who knew her.

But even Rose was not aware of the long sleepless nights and the sense of a world closing in so fast that it was almost suffocating her niece.

As had been so often the case, it was a sense of duty that came to Kate’s aid as she walked into the light and warmth at 17 Khyber Road. The single driving force of her life now was to try to limit the damage of her husband’s departure on Gus and Fiona.

Not that she had any sense they appreciated it. Her thirteen-year-old son was hunched over his iPad on the sofa in the corner of the kitchen. Kate gently removed the headphones from his ears (which, she could not help noticing, were full of wax). ‘What are you watching?’

‘Mission Impossible.’

‘Sounds like my life.’

He didn’t smile. ‘Is that a joke?’

She tutted in despair. ‘Where’s your sister?’

‘She went out.’

‘Where? I told her—’

‘That is a joke. She’s upstairs. With Jed.’

‘Oh. What time did he come around?’

‘About ten minutes ago.’

Kate went to put on the kettle. ‘What did you have for supper?’

‘Salmon, like you suggested.’

‘Did she eat her—’

‘I’m not going to be your snitch, Mum.’

Kate came to sit next to her son. ‘You know this is serious, right? They say anorexia is the hardest mental illness to treat.’