A look of mortification flashed across Sally’s face. ‘I wouldn’t accept anything. I should be offended just to think of it.’

Knowing better than to argue with Sally, Lou backed down. ‘Very well,’ she said. ‘But you can’t refuse this.’ She put her arms around Sally and pulled her close. After an initial flinch of resistance, Sally gave in to the hug. A lump rose in Lou’s throat. ‘You take good care of William and that little boy of yours. I’m going to miss you all so much.’ She closed her eyes and felt Sally nod. When they parted, Sally quickly wiped her eyes with the edge of her hand.

‘You should go,’ Lou said, her voice hoarse.

In a final show of dignified deference, Sally curtseyed. ‘Very good, Miss,’ she said, un-spilled tears in her eyes. She turned, collected her tray and headed away down the stairs.

Lou ran the rest of the way up the stairs and emerged at the far end of the landing. She flicked the light switch and made her way along the corridor in darkness; her senses alive, ready to run should any noise sound like an approaching person. Once safely inside her room, she sat at the dressing table, and laid out three sheets of paper. It was clear that she couldn’t seek out any of her friends to say goodbye in person; it was a risk too far.

The first letter, to Lady Mandeville, was short: a couple of polite sentences thanking her for her hospitality and apologising for her hasty departure. The second letter took much longer to write. What could she say to Charlotte that wouldn’t alarm her? She could hardly make predictions about the future without sounding insane, confirming any such idea that George may have already planted. She settled on a rousing letter, cheering Charlotte on, telling her to make the most of her life, to fulfil her potential, to warn her away from being ruled by men as best she could. She made no promise of returning but neither did she say that she wouldn’t. She stopped short of a direct warning to stay away from George.

Let nobody ever tell you how to live your life. Never settle for second best. Fill your brain so full that you feel it will burst and then fill it some more. When you have finished, put everything you have learned to good use. I hope you will remember me fondly as I will remember you. Your friend forever, Louisa.

After sealing both letters in envelopes, Lou looked down at the third sheet of paper. Its blankness stared back at her, watching, waiting. She drew more ink from the squat bottle into the pen and placed the nib to the paper. A blot began to form, growing, spreading. The paper soaked up the ink she could not use to form the words she so desperately wanted to say. What she felt for the intended recipient of this letter couldn’t be contained on a single sheet of paper. The outpouring of words would spill out over the desk, pour on to the floor and surround her until she drowned in them. It would do neither of them any good for her to lay her soul bare. She had been brought back to tie up a loose end, not unravel another thread.