On the Wednesday afternoon, as Mrs Elliot dressed for dinner, I called upon her and was most relieved to find her alone, but for Victoire and the friseur who was arranging her hair.

I resolved to tell her instantly, not to demur or gossip or complain about the heat which lay as heavy as a fur pelisse across Paris. I took my seat, drew in my breath and recounted the contents of Madame de Buffon’s letter to her, before announcing my intentions. After I had said my piece, I sat with perfect stillness, anxiously awaiting her response.

At first she made no remark. Her mouth remained set. Her flinty eyes appeared as flat as a calm sea. Then a gentle smile raised her cheeks.

‘Ma fille,’ said she, ‘this is the opportunity I had hoped for you . . . but I had not imagined it would come to pass so swiftly as this.’

‘But it is on your behalf that I have agreed to assume this errand,’ I attempted to correct her, wearing a bright, conciliatory smile of my own.

She lowered her gaze in a shy, grateful manner which I had not before witnessed. It was a moment more before she spoke.

‘Ma chère fille, I am genuinely blessed to call you a friend.’

‘It is I who is blessed to know such true kindness, as I have never before, my . . . chère maman.’

She lifted her gaze again and held her hands to me. I took them into mine, as if sealing the pact between us.

‘You must write to me frequently.’

‘But of course . . . I shall miss you every day!’

‘Tell me everything. Tell me what poison La Buffon drips into his ear. Write to me of what Orléans says to you, of their conversations. I must consider how to make amends with him. You must not attempt it yourself, but allow me. I know the words to speak to him, how I might soften his heart. Do you understand, my dear?’

‘Yes,’ I agreed eagerly.

She pressed her hands in mine and beamed.

‘You must make use of every advantage given to you, Hetty. Whatever is requested of you . . .’

My expression began to fall at what she insinuated.

‘You understand, do you not? Ingratiate yourself and the rewards will be great.’

‘Yes,’ I said.

‘Very well, then.’ She sighed, and I rose from my chair.

We then embraced, as might a devoted mother and child, and bid each other tender farewells.

‘Henrietta’, she called out to me as I advanced towards the door. ‘Do make certain not to leave your secrets exposed to La Buffon’s prying. Direct your letters under cover to Thérèse. Instruct her to bring them to me here. La Buffon will be most suspicious of you. If you are seen to be corresponding with me you are likely to forfeit her trust.’ Her face turned quite solemn. ‘Proceed with great care, my dear.’