Angelica smiled. “You have to be wary of these conspiracy theories,” she said. “Most untoward events have a very simple, rational explanation. The Pope's visitor probably had a heart attack - it was probably nothing to do with the coffee. And John Paul the First himself was certainly not murdered. We know that for a fact.”

William raised an eyebrow. “How can you be so sure?”

“Because we have our man in the Vatican,” said Angelica. “We had a very full report from him, and he indicated that all those rumours were groundless.”

William could not conceal his surprise. “You have your man in the Vatican? A spy?”

Angelica shrugged. “Of course we do. He's a highly placed cleric. A monsignor. He works in the Holy Office.”

“And he spies for you?”

Angelica held up a hand. “Steady on. I wouldn't call it spying. He reports, that's all.”

“But what possible interest do you have in Vatican affairs? They're hardly a threat to our security.”

It was Angelica's turn to raise an eyebrow. “You think not? You should study history, William. The Vatican has been meddling in the affairs of other sovereign states for centuries. They have a very clear idea of what's in their interests and how to achieve it. And why not? If you look at it from their point of view, why not attempt to ensure that things work out in the way they want? Everybody else does precisely that.”

William was at a loss as to what to say. He was astonished by the disclosure that Angelica had made, but there was something else that was also puzzling him: why was she telling him all this, and, more than that, why had she come to see him in the first place? This, he thought, was not a purely social call.

He glanced at her tea cup, which was empty. “More?”

She slid her tea cup towards him. “You may be wondering-”

He cut her short. “I certainly am.”