‘Sir Alan?’ He turned back to her. ‘How did you know my relationship with Sergei was more than just a friendship? I mean, right back at the start, you came to my office and you spotted instantly that he was my source for that meeting on the yacht and you understood that I might have been susceptible to being misled as a result of my feelings for him.’

‘Instinct,’ he said. ‘I’ve been in this business a long time. I meant what I said. Come down and see me. We’ll talk.’

It was a long journey to see Ian Granger’s former wife at her palatial surroundings in Wiltshire so Callum and Julie filled it by establishing, with great discussion and argument – and at some length – a ‘definitive’ list of the ten greatest films, TV series and songs of all time. Kate’s contributions were Mamma Mia, I Have No Idea and ‘Dancing Queen’ – ‘of course’ – respectively. She didn’t really understand this mania for creating lists. What was the point?

It seemed relevant somehow that Callum’s favourite films were all spy yarns of the most exaggerated variety: ‘The Bourne Supremacy, Casino Royale, The Bourne Identity, in that order.’

They had met in the office just after nine, with Shirley Grove, and Kate had briefed them on the conclusions she had reached from her survey of the files the previous night. She didn’t tell them of her breakfast meeting with Ian, though it had seldom strayed far from her thoughts. ‘I’ll leave you to explain what you’ve discovered in mine,’ Kate told Grove icily, as she pointed at the file on the corner of her desk. Just for a moment, as she reflected upon Ian’s evident determination to clear the Service’s reputation, she wondered whether he and Shirley Grove might be working hand in glove. But wasn’t she trying to resurrect the very subject he was trying to bury? Except, of course, having Kate publicly exposed as Agent Dante – a kind of criminal mastermind – would suit everyone.

Grove didn’t dignify that with a response.

‘It’s not that anything in there proves Ian Granger is our man,’ Kate had concluded. ‘Merely that it provides quite a convincing narrative that he might be.’

Celia Granger had moved very fast since divorcing her husband, relocating her family and business to this bucolic site just west of Salisbury. The home was a handsome red-brick old rectory with wisteria climbing its façade, the business housed in a huge renovated barn on the other side of the drive. At the front door of the main house, a Filipina maid or housekeeper directed them to the reception area at the front of the barn, where they sank into low-slung sofas around a rattan and glass table furnished with fashion and lifestyle magazines of every hue.

The young receptionist offered them coffee, and a few minutes later, they were ushered into Celia Granger’s office and installed in another low-slung seating area, which afforded a view of a cropped wheat field that sloped gently down to a copse and river in the distance. It was idyllic.