‘I should congratulate you on such a successful career. Meteoric, one might say.’ Sara returned a formal smile. The beakiness was what struck her. A narrow, flat body – skeletal even, a reminder of Marion – wearing the loose-fitting blouse and black trousers to disguise it. A matching black jacket hung on the back of her chair. It was her nose more than anything – longish, with a distinct kink halfway down, sunken grey eyes behind contact lenses, thin lips, imperfect teeth she seemed anxious not to reveal, a hard chin but not out of proportion to her overall bone structure. It was possible that, as a younger woman, the emaciated angularity could have been attractive; if so, that had worn off and she presented a forbidding figure, kept lean by an excess of nervous energy. Sara tried to picture her and Kareem standing together when they first encountered each other thirteen years ago, she some ten years older than him. He might have seen her as a challenge – a white-skinned woman in a position of secret power, a conquest in waiting.

They sat, Isobel on one side, Patrick and Sara opposite.

‘This is not an official visit,’ she began. ‘I particularly didn’t want to invite you to Thames House.’ Patrick and Sara exchanged a glance, a silent acquiescence to let her make the running. ‘If you would prefer that we go out of this office, perhaps for a coffee…’

‘There appears to be coffee here,’ said Patrick tersely, as the door opened to reveal Clovis bearing a tray.

‘I realise this… this situation may seem odd.’

‘Could I get one thing clear, Dame Isobel?’ said Sara. She couldn’t imagine calling this woman by her first name only. ‘Unofficial or official, is this meeting on the record or off it?’

‘I would like to give you some guidance which will save you both time and resources. But I must ask you to keep any information I give to yourselves.’

‘So this is a meeting that didn’t happen,’ said Patrick. ‘A discussion that didn’t take place.’

‘Correct.’

‘Are you intending to impart information involving potentially illegal activities?’

‘No.’

‘If you were to, there’d be an obligation on us to report it to the police.’

‘Correct. “Secret” does not, and never can, mean “illegal”. Those are the rules under which the Security Service operates.’

Patrick thought of the contract with Kareem. ‘Sara?’

‘I’m OK with this.’

‘Thank you.’ Isobel composed herself. ‘I understand that you have become interested in the secret arrangements of which you are aware, Patrick, with Kareem bin-Jilani.’

‘Could I inquire how you understand that?’ asked Patrick.

‘Yes,’ she replied, now asserting herself. ‘By legally authorised surveillance of a person suspected of a criminal act.’

‘What criminal act?’ asked Sara.

‘A breach of the Official Secrets Act.’

‘You’ve been bugging Walter Thompson,’ said Patrick.

‘You can’t expect me to comment on that.’