Miss Lister’s posthumous fidelity clause can be viewed in her will at the With Love exhibition at the National Archives in Kew, west London, from today.
It is on show with dozens of love letters and other fascinating documents which depict historical relationships.
Lister scandalised society by dressing in masculine clothes and having relationships with women from the age of 15. Neighbours dubbed her Gentleman Jack. She wrote of her affairs in an 8,000 page coded diary.
In the TV show, Lister has an on-off affair with Miss Walker, played by Sophie Rundle, before they take vows of commitment to each other. Vicky Iglikowski-Broad, principal records specialist, said Gentleman Jack helped shape the modern image of a lesbian.
She said: “Ultimately, she bequeathed her substantial estate to her friend Ann Walker.