Edith Lanchester (1871-1966) was a British socialist and feminist.
She was born to a prosperous architect and grew up in Battersea, south London; she became a prominent activist in the Marxist Social Democratic Federation (SDF).
By her mid-20s she was a schoolteacher, then worked as a secretary to Eleanor Marx, daughter of Karl Marx and a prominent activist in her own right.
In 1895 Lanchester caused a storm when she announced that, in protest against Britain's patriarchal marriage laws, she was going to cohabit with her lover, an Irish factory worker, James Sullivan. Her socialist feminist