Picasso, Braque and Bonnard are among some 37 works collected by Illa Kodicek (1899-1990), a Czech emigree who founded a corsetry business in London. Many of the artists, ranging from the Expressionists to the Surrealists, were relatively unknown when she bought their work.
The paintings have not been seen in public since she acquired them: they filled her flat off Piccadilly, London. Among the works are Picasso's sensuous Le Repos (estimate, pounds 700,000 to pounds 1m); Braque's Nu Assis (pounds 250,000 to pounds 350,000), inspired by ancient Greek female figures; and Bonnard's gentle landscape Cabanons au Cannet.
Kodicek, who moved in the social circles of Freud and Kafka, fled Prague in 1938 with her second husband, Josef Kodicek, the Czech writer. They came to London with little money but after building up her business she was able to indulge her passion for art.
The collection is being sold on behalf of The National Association of Boys' Clubs, to whom it was bequeathed in 1990. James Roundell, of Christie's, said: 'It shows that it was possible to put together a major collection without great financial outlay.'