She watched as he poured the tea into her cup. “Well, I'd expect you to wonder why I've come to see you and also why I'm speaking about my work - which is meant to be confidential.”

He nodded. “I was.”

“You know that we've been watching you?”

William gasped. Had he been under suspicion?

Angelica was quick to reassure him. “No, we don't have anything on you. We call it a friendly watch. Perfectly friendly.”

“Then what … ?”

“We want to ask a favour,” Angelica said. “You can say no, and we'll leave it right there. But if you say yes, then … well, HMG would be terrifically grateful.” She paused, watching him closely. “What did JFK say to his people at his inauguration? 'Ask not what your country can do for you, but what you can do for your country.' He said that, didn't he?”

“I believe so,” said William. His mouth was dry, and he found himself thinking, somewhat uncomfortably, of boeuf stroganoff.

For a few moments after Angelica's revelation, William said nothing. He had read of MI6, of course, and had passed its building near Vauxhall Bridge on numerous occasions. For an organisation whose business was secrets, the building seemed hardly appropriate, being, as it was, quite open-looking, and apparently not at all suitable for shady work of the sort that MI6 - and presumably Angelica herself - engaged in.

He knew, as everybody did, that it was MI6 headquarters and had speculated on what went on within. He had seen people going in and out of the front door - quite openly - and they had seemed to him to be no different from the people who went in and out of any building in the City, for example. And perhaps their jobs were not all that different from the jobs of any others among the legions of civil servants who worked in London. They attended meetings, no doubt, wrote memos, and strove, he imagined, to meet targets. At the end of the day they probably went home in much the same mood as everybody else, leaving behind the cares of the office.