The multi-phase Clarendon Gas Works project poses challenges due to the combination of existing derelict gas works on site and the nearby Moselle River. It required close collaboration with the Environment Agency, Highways Agency and Network Rail. The Clarendon Road site, situated to the South-West of Wood Green, was previously home to 44m gasometers. The area will be revitalised with public and community spaces that celebrate the identity and history of the area and over 1700 homes in residential blocks between two to 15 storeys. Walsh has been heavily involved with structural and civil engineering for the project from its early stages. We drew on our experience of developing buildings on gas holder sites and large London mixed-use developments. Our teams used lean design to develop achievable plans for substructure, superstructures and bridging foundations. We navigated obstructions across various gasholder pits, for example. Approximately 50% of the site contains basement car parks next to railway lines requiring approval from Network Rail. We were instrumental in gaining this third party substructure design approval. Our drainage strategy, including diversions, also required approval from Thames Water. Finally, our scope also covered extensive S278 and highway works. We proposed adoptable highway roads and cycle routes throughout the development.