The letters sent by the English composer Michael Tippett from Wormwood Scrubs Prison, where, a conscientious objector, he spent two months in summer 1943, form a remarkable and important sequence, illuminating not only Tippett's life and compositions but the experience of a gaoled objector to the Second World War. Four prison letters had been thought to survive, documenting in detail his imprisonment, which included turning pages for Benjamin Britten during a recital in the chapel, and conducting the prison orchestra. In 2023 a fifth letter was found, its discovery reported in the national press.1 Its publication is intended to complement the previously released documents, completing what is now a series of five until such time as a collected edition of Tippett's letters, of which only a fifth has seen print, can be undertaken.2