The papers include: correspondence; domestic and personal papers; early family correspondence, particularly among ELS's mother's relatives; diaries, including ELS's journals as a liaison officer with the French from the First World War and as Head of the British Mission to de Gaulle during the Second World War; some political papers and military maps; speeches and articles; manuscripts of books and short stories, with literary correspondence and original and copied source material from Spears's work as Churchill's personal representative to the French Government in 1940; press cuttings; photographs; business papers, mainly relating to ELS's chairmanship of the Ashanti Goldfields Corporation and the Institute of Directors.

The archive also includes the papers of ELS's first wife, Mary Borden, particularly her correspondence with ELS, and her letters and diaries relating to her First World War hospital and the work of the Hadfield-Spears Mobile Hospital Unit during the Second World War.