A gasp escaped me, as if my heart had been punctured and all the air released from it. My jaw began to tremble and I clenched it tightly.

‘That first occasion when I brought you to the Palais-Royal, do you not recall it? I drew your attention to a print-shop window: Henry Tyrone, a purveyor of Jacobin slander and filth. Your paramour poses as one of two American gentlemen who are known by this name, father and son. More ardent lovers of the Revolution you will not find. Oh, they play their roles exceptionally well. There is no club or society to which they are not admitted. They sit at the table of Marat, Vergniaud, Danton and Robespierre – why, that scoundrel venerates your beloved.’ She laughed. ‘I made certain to catch his eye that day when we passed before the shop window. Lord Allenham observed you with me. I wished him to know that you were in Paris, to warn him.’ She raised her gaze to mine and her smile retracted. ‘Henrietta, he is a spy for His Majesty King George. As are you.’

This blow fell hard upon me, perhaps with more force than all the others combined. I have mused upon it over the years and concluded that there is no suffering in life worse than a sacrifice made in vain. It sickened me to retrace my steps through the twisted tangle of deceits, to consider each decision I had formulated and each deed I had committed in the hope of rendering myself worthy of her affection, of honouring a debt which never existed. To have abandoned my principles, to have lain with a man I did not desire, to have betrayed a true friend, to have nearly lost my life, all on account of falsehoods. It was unspeakable, unconscionable, cruel.

My eyes spilled forth their tears and still she sat, impassive, with a stare as cold as a cat’s.

‘My dear, the intelligence with which you have provided me has succeeded in winning me great favour with His Majesty’s Government. Until I had made your acquaintance I had relied solely upon my own wits in gathering such information, but Orléans ceased to confide in me and Mrs Meyler did the bidding of whomever paid her the most handsome sum. Child, there are spies everywhere in Paris. They work for everyone, from our King to King Louis, from the Austrians to the police and the Jacobin Clubs. There is not a corner in all of France free of infestation. This nation daily talks of its new-found liberty, but still tyranny prevails.’

She then rose from her chair and moved across the room to an escritoire with a locked glass bookcase atop it. She removed the key from a dainty chatelaine at her waist and opened it, taking into her hands the book-sized portrait of her young daughter, Georgiana.