‘Wrong. The Morahan Inquiry has been cheated of its duty to examine a vital witness.’

‘In that case, I must give you the fuller context. Please keep it to yourself.’

‘I’m not willing to guarantee that. Not until I’ve heard you.’

‘Should I trust in your good sense and your patriotism?’ Sara looked straight into her eyes, giving nothing. ‘I think I should,’ said Isobel. ‘I see an empty bench. Shall we sit?’

They spread themselves and Sara’s cardigan to fill it.

‘For a decade,’ Isobel began, ‘Operation Pitchfork was a success – vital to our security. Kareem performed services to this country, at great personal risk. He neither could, not would, ever be prosecuted. Back in 2016, in the weeks after my appointment as DG – but before I took it up – I continued to handle him. During those weeks I became worried by some aspects of his judgement and behaviour.’

‘What aspects?’

‘His character streaks of domination and manipulation were in danger of becoming overbearing. And potentially damaging. You may recall these from your own youthful experience.’

Sara felt her nakedness in the presence of this woman. ‘Did he speak to you about me?’

‘Yes, often. He was still bewitched by the thought of you. He told me everything. Or, perhaps, his side of it. He always seemed to want some kind of reckoning because you walked away. I told him that was a waste of his energy.’

‘I was lucky to get away.’

‘Perhaps you were. For me, it was different. He owed me. And though it was an exception for an agent handler, I decided to have a relationship with him if it kept him in play.’ The trace of a smile showed in a squeezing of eyes and pursing of lips. ‘I cleared it with the relevant people in the organisation, though not without initial difficulty.’ The smile faded. ‘To continue. Having created his death in the drone strike, I decided to keep Kareem within my sights and monitor him. His new identity allowed us to parachute him into two City directorships to occupy his mind. He was no longer on the Security Service staff or payroll though we were honouring his pension. Not that he needed the money – he spent half his time learning aerobatics.

‘Then, though we succeeded in delaying it for a while, a naive government finally insisted on the foolish initiative that led to the Morahan Inquiry. Kareem saw a chance to become involved again in the manipulations he enjoyed. I’m still not fully clear on his motives. Perhaps they changed as events unfolded. He may have been angry with MI5, me included, for stopping Pitchfork, and wanting to make trouble – not much trouble, just enough to annoy us. He may have liked the idea of feeding the Inquiry in a way that would poison it. And he realised he might be able to use it to reach you.’

‘But that was all so long ago.’