In the early years of the Second World War, Leslie Martin complied a photographic album to record the architectural work done in partnership with his wife Sadie Speight since 1934. It amounted to ‘quite a lot’, he wrote to Ben Nicholson. Thirty years later, Martin — by now Professor of Architecture at Cambridge and Head of the Land Use and Built Form Studies Centre — was to dismiss his pre-war work as ‘really insignificant in scale’. Martin’s own book, Buildings and Ideas, 1933–83, contains a highly selective account of this early period. This partial view has been further obscured by the persistent misdating and misidentification of the practice’s two most substantial pre-war houses — Brackenfell in Cumberland and Four Acres, North Ferriby, near Hull — in the literature of the Modern Movement in Britain. Of the two, Brackenfell is of particular interest, as the house of Alastair Morton, design director of a textile firm and novice painter. Martin’s own brief comments and the volume of drawings which survive for Brackenfell suggest that this was an important commission for Martin and Speight, and one which precipitated a significant shift in their approach to architecture. However, our inadequate knowledge of the work of the partnership means that the house has so far eluded full analysis. This article proposes to disconnect the evidence of this building from Martin’s subsequent career and architectural theories, and to view it instead in the context of its period. Using Brackenfell as its focus, the article aims to clarify Martin and Speight’s evolution as designers, and to probe the significance of their association with a distinguished group of artists during the late 1930s.