The agent in Chile had made Ian in a way Kate had never appreciated – and turned the course of his career. How easy it would have been for Moscow to make that happen.

It didn’t prove he was Agent Dante, of course, but it gave her nothing to dismiss the idea, either. And the timeline worked: recruited in New York in the mid-nineties, as Natasha Demidova had suggested, then super-charged by the recruitment of the agent in Chile.

Kate swapped Ian’s personnel file for the one covering his vetting over the years. He had first, of course, been assessed upon entry to SIS, a process repeated every five years or so, or after any particularly difficult, complex or controversial assignment.

The first positive vetting contained detailed accounts of conversations with Ian’s school headmaster and Oxford tutors. All praised his intellect, though the Oxford dons questioned his application and commitment, suggesting he was easily bored by assignments that didn’t interest him. The headmaster gave a by and large positive account of his character and abilities, though he stressed Ian’s weakness was a certain degree of social insecurity and the desire to be liked and respected by his peers. Ian’s mother had nothing but praise for her son, whom she clearly doted on, and his stepfather almost nothing good to say about him at all. This, the assessor concluded, was pretty much par for the course in a broken family – including the social insecurity – and not to be considered a bar to his recruitment.

Subsequent vetting had been conducted only twice outside the five-year routine. Once was after New York, the second time after his assignment to Paris. Kate was not surprised to learn that, in both cases, the reason was reporting by ‘colleagues’ of barely concealed affairs with diplomats of other legations – a Czech in New York and a Dutch woman in Paris. The assessor in both cases took a lenient view, concluding that Ian’s behaviour should be considered a private matter that ought not to impinge on his career progression.

Kate got up and went to make a cup of coffee. She had sent Julie and Callum home with the instruction they should all meet to regroup early tomorrow, Julie in the meantime tasked to arrange a meeting with Ian’s ex-wife. So, Kate had the office to herself. She watched the machine spit out the dark liquid and thought how typical it was for the – no doubt male – assessor to conclude without prompting that Ian’s affairs were a personal matter. She had absolutely no doubt that a woman of the time would have been judged differently and she wasn’t completely certain that that had changed.

She returned to the desk and switched files to consider the career of her friend and mentor, the former chief of SIS, Sir Alan Brabazon. He had been educated at Sherborne School, where she and Rav had established he was a close friend of the prime minister, and Manchester University, where he had studied history. He had joined the Service in 1986 after writing a personal letter of application.