One night she woke only an hour after retiring, with a new torment; her hands and feet possessed by a sense of heat and ferocious itching. She lay unquiet, trying to stave off the desire to scratch, and failing. As soon as she had attacked one spot with her nails, another began to itch. Then it was the turn of her scalp and the V of skin just beneath her throat.

In desperation, she threw back the bedclothes, and found a little relief in the chill air on her inflamed skin. Mr Collins was away overnight on a visit to his bishop, and Charlotte felt suddenly trapped, stifling, a bird caught in lime. She had to get out. Surely she could leave her sleeping children for an hour, with Katie slumbering in the attic room above?

She did not dress, but wrapped a heavy mantle and shawls over her nightgown, and went downstairs as quietly as possible, pushing her feet into boots kept in the mudroom, finding mittens in an apron pocket. She slipped out the back door, leaving it unlatched. No thieves would be abroad in this weather; the cold was intense, bracing, overwhelming – as she needed it to be. It bit at her skin, wrenched tears from her eyes, insisted that she keep moving.

She found the ruts in the lane difficult to navigate by faint starlight and a half-moon only, and turned into Rosings park; she would follow the paths there for a while, until the restlessness and burning left her limbs. She soon struck out across the frosted grass, the crunch under her boots as satisfying as the lungfuls of icy air she sucked in.

The silence was intense; no sleepy chirrup of bird or chime of church bell broke the spell of deep night. Only the sound of her own steps, the blood rushing in her ears, echoing her heartbeat.

And then her heartbeat took on a life outside her body, thudding into a distant gallop. It took a few minutes before Charlotte realised she was indeed hearing the drum of hooves, approaching fast. She had no time for more than a moment’s panic – what would highwaymen be doing on the Rosings estate? – when the shape of a horse and rider loomed, silver and black in the black and silver night, tangible more through scent and sound than vision. There was a long harrumphing snort, the equine form convulsed as it shied, a figure tumbled from its back with a thin cry, and the rhythm of hooves broke apart in panic.

Charlotte ran for the broken-bird figure on the ground, only to be sent back by the voice, which, to her amazement, belonged to a woman: ‘Catch him! Catch the damned horse, for God’s sake!’