35 Marylebone High Street is a nine-storey, residential-led mixed-use development in central London. Attaining Code for Sustainable Homes Level 4, the residential units incorporate high levels of insulation and airtightness, as well as triple-glazed windows and roof-mounted solar panels. The distinctive 1930s Marylebone High Street façade was retained and refurbished, while an out-of-scale rear extension was replaced with a sustainable new building that is more sympathetic to its mews setting. The Schüco Excellence Awards jury complimented the scheme on its carefully considered and sensitive approach to façade design and contextuality. Special praise was reserved for the high-performance replacement windows, which resolve important aesthetic, performance and environmental issues.