The papers of David Thomas cover the years 1956-1979. They include correspondence files, draft articles for publication, administrative papers, and a selection of digitised slides. The administrative papers date from Thomas’s time as Chairman of the RGO section of SRC branch of IPCS. They give an important insight into RGO staff concerns about the future of the organisation and of British Astronomy in general. Particularly significant are the files on the separation of the posts of Astronomer Royal and RGO Director, and on the Northern Hemisphere Observatory Project.