Hi Sara, sorry that you’ll be the one left with this mess. It’s finally over for me. There’s a sadness in my life that won’t go away and I can’t go on. You’ve been a great colleague, however briefly. Thanks for that. Patrick x

She read it and cried for longer than she could remember crying since she had been a child. A good – a very good – man had died, and had been beaten in the process. She understood that a part of her had died with him.

She went to the bathroom, showered, dried the tears and collapsed on her bed, not expecting sleep to come easily. Three thoughts kept revolving. How much he must have frightened them. How clever they’d been, particularly with that text. How she must stop herself feeling powerless. She set her alarm for 8 a.m.

Three hours later, she was sitting on a stone resting beneath one of the Temperance Fountain’s four lion heads. She discarded her cardigan and lay it beside her – the day was hot. Though she watched, she saw nothing till the tall, slim figure drew alongside, hovering over her – long linen trousers, a cream blouse, an elegant white hat with broad brow and large sunglasses.

‘Hello, Sara.’

Sara stood. ‘Hello, Dame Isobel.’

‘As before, just Isobel. Also as before, this discussion is not happening.’

‘Will it be the truth this time?’

‘Would you mind if we walk? It won’t take long. Perhaps towards the bandstand.’

They rose and walked silently until they were sufficiently alone.

‘I’m very sorry about Patrick,’ said Isobel.

‘Are you?’ said Sara. Her tone was flatter than the grass.

‘Of course. He was a decent man and a good lawyer.’

‘Decent man. So everyone says. When did you hear?’

‘I heard the news around 6 a.m. I was deeply shocked.’

‘Though not surprised.’

Isobel stopped in her tracks. ‘Sara, I know you’ll find it hard to trust me after what I told you about Kareem’s death. That remains a necessary fiction – we must maintain it. But I have something important to tell you. At this very moment, Kareem – under his new name, of course – is being deported.’

‘Deported?’

‘Yes, returned, whether he likes it or not, to his home state.’

‘Which is?’

‘That need not concern you. Let’s just say the Gulf.’

‘Why?’

‘For suspected breaches, in recent weeks, of the Official Secrets Act – which he signed up to on joining the staff of MI5.’

‘You mean Sayyid.’ Isobel stayed silent. ‘Then you should be prosecuting him.’

‘It’s been decided that would not be in the public interest.’

‘Don’t you mean special interests,’ said Sara.

‘I understand your cynicism. It would never be provable in a court of law. The decision was taken rapidly and unanimously this morning, at the highest level.’ Sara said nothing. ‘I’d hoped you would feel reassured by this news,’ continued Isobel.