This thesis provides the first comprehensive exploration and assessment of the speculative office building in inter-war England. Both instruments of revenue and containers of office space, buildings of this type and period have been largely absent from the literature of architectural history, despite their growing importance, economically, functionally and architecturally. Similarly, neighbouring disciplines, including urban and economic history, have undervalued the significance of this specialised building type between the wars. This study offers a more complete account and understanding of how and why these often-imposing buildings were procured, designed, built and used, where this occurred and which firms and figures were most active in this urban developmental process. The focus is predominantly large English cities, especially London, a reflection of both the geographic locus of speculative offices in this era and the interests of Historic England, the Government’s statutory body and co-sponsor of this study. However, by way of context, comparison and insight, examples and experience from further afield, especially America, are drawn into the narrative. Indeed, English speculative offices of this period can be considered as competing, vertically-challenged investment skyscrapers, machines to make urban land pay (to paraphrase the skyscraper architect Cass Gilbert), and ‘business rivals, competitors for tenants, light and air, and prestige’ (to quote skyscraper historian Carol Wills). The influence, direct and from afar, of American practice on the planning, design, marketing and management of rentable office space in inter-war England was remarkable and justified a transatlantic visit to examine a little-known journal that illuminates this relatively unfathomed area. Besides archival information preserved in record offices, other, less-thumbed contemporary sources include journals serving the property market and office equipment sectors and those lesser architectural and building journals with more modest lifespans or reach. Examination of the exteriors of surviving buildings, and illustrative interior photographs and floor plans in modern estate agency literature, provide additional, or sometimes the only detailed information, on some buildings.

The thesis is both anatomical and thematic in approach and structure. The introduction establishes the need for the study, and its place within the literature, published and unpublished. The first chapter, prefaced with a historical overview of pre-First World War developments, considers the increasing and geographically concentrated demand for office space in the inter-war period, and how speculative offices met this with increasing efficiency – not only through bigger, better buildings but also in terms of how they were marketed and managed. The second chapter focuses on the leading economic actors in the property development process, the developers, bringing to light the activities, portfolios and personalities of some of the principal firms and individuals behind metropolitan and provincial office blocks. Chapters three to seven are a detailed survey and analysis of the architectural design and construction of inter-war speculative offices, with a separate but interlinked treatment of their planning, construction, external and interior styling, and essential service technologies. Running through these mostly chronological accounts are questions and considerations of cost, efficiency and influence, and factors limiting or pushing built form and expression, such as the legislative environment, size and shape of building sites, and the freedoms accompanying framed construction. The thesis concludes by drawing out and summarising the key findings – including a rebuttal of the pronouncements of financial journalists and property market historians concerning withered speculative development between the wars. It then considers broader themes: the impact of the First World War and its aftermath, American influence, speculative offices and organisational change, and the increasing congruence of speculative and custom-designed offices.