Sir Alan was at the last security barrier, readying himself to leave to get back to the hospital. Rose was beside him, her arm still in a sling from the kidnap. The doctors had made clear to all of them that the mental scars would take much longer to heal.

Rose touched Kate’s shoulder in support. Sir Alan did not appear to know what he should do. ‘I thought I’d better pipe you out,’ he said.

‘Off, I think.’ He looked confused. ‘Don’t you pipe someone off? It’s a naval term.’

‘Yes, yes, perhaps so.’ He stared at the floor. ‘I’m sorry it had to end like this, Kate.’

‘I’m not. I should have made this decision a long time ago.’

‘Are you certain you’re doing the right thing? I’m sure my successor—’

‘Your successor?’

He glanced at Rose, as if it was a decision they had reached jointly. Not for the first time, Kate wondered just how far the friendship between her aunt and their superior extended. But she choked off the train of thought. Not her business. ‘I’ve taken the decision to stand down,’ Sir Alan said. ‘The search for my replacement has already begun.’

For a moment, Kate was less sure of her own decision. Perhaps it was the old competitive spirit or, as she would have preferred to see it, her conscience. ‘So Ian got what he wanted.’

Sir Alan glanced at Rose again. ‘We can make sure there’s a future for you here, Kate.’

She wavered for only a moment more. ‘No,’ she said firmly. ‘To answer a question Stuart once asked of me, I don’t think in the end it is possible to be a warrior for truth and the mother I’d like to be. And if I must choose, then I know what it has to be.’

Kate could have told Sir Alan – and, indeed, Rose – that an agreement to allow Stuart to come and go unhindered in continental Europe had been the explicit quid pro quo with Shirley Grove for lying through her teeth a few minutes ago or, as Grove herself had put it, ‘telling the complete truth of the entire affair’. But they would, no doubt, have guessed as much.

Kate kissed Sir Alan. ‘Bloody good luck, my friend,’ he said.

She hugged her aunt, who whispered only, ‘See you at home.’

She nodded at the security guard, who let her out of the building for the last time.

She swung right and headed westwards towards Battersea in the drizzle.

It was a gloomy night, but warmer than it looked, a close humidity wrapping the capital in its suffocating embrace. Kate shrugged off her coat, slipped it over her arm and glanced back at the organization to which she had devoted most of her adult life.