|Cambridge is a historic city in the UK with an international reputation. The CB1 development is a major real estate regeneration project around the train station aiming to provide a gateway to the city. Once complete it will provide over 50,000 sq m of offices; 5,000 sq m of retail; 1,250 student units and 330 residential dwellings. When creating such a masterplan on a brownfield site with multiple existing buildings and in a sensitive context, multiple decisions to demolish or adapt need to be made. This paper tracks the history of the CB1 development through a review of planning documentation and media articles, and through interviews with key stakeholders, including the developers, town planners, architects, engineers and local campaigners, identifying where and how key decisions relating to adaptation and demolition were made. The case study reveals complexities of decision-making in a real-world context. For example, for some of the existing buildings there were conflicting viewpoints about their future. The demolition of a Victorian terrace in favour of two new-build office blocks saw opposition from a local campaign group and the city councillors. However, the planning refusal was taken to appeal by the developers, who were then granted permission by the Planning Inspectorate. Arguments put forward included the lack of architectural significance, supported by the building not being listed and the public benefit brought about by demolition. The paper also explores the technical aspects associated with buildings which were demolished or retained through the creation and analysis of a database of existing and new buildings. The exploration builds upon international research analysing features that increase adaptation potential. Considering such aspects as, the condition of the building; floor to ceiling heights; standardised floor plates; and intangible values, such as architectural significance. The paper therefore assesses the CB1 development from both a technical and social perspective. The conclusions encourage actions to ensure holistic and sustainable decision-making in the future, recommending: the need for early stakeholder engagement; clarity on the strength of outline planning permission; and the recognition that heritage conservation and new build can both contribute to place-making. The paper also demonstrates the need for compromise, with inevitable conflicting viewpoints on a development of this scale.