The first chapter of an evolving urban story, 10 New Burlington Street (W4) is a layered reinvention of an urban block in central London. A triple-glazed skin – gently curving inwards at top and bottom – emerges behind an ‘L’ of the retained corner façades of a substantial city block to define a new volume that connecting a collection of secret garden spaces, which remake the previously unused Burlington Mews. Within the new volume, six new floors and a core are inserted, centred by a five-storey atrium clad on one edge in scalloped blue faïence tiles that to soften light and surface. Below, forgotten, listed vaults are re-inhabited and put to new uses. Above, an exposed steel structure on the sixth floor resolves the curving geometry of the facade while opening up the building’s perimeter to expansive views and a rooftop terrace. In territory originally defined by Nash, W4 arranges 40,000 square feet of new retail space at basement, ground and part first floor below optimised office floorplates totalling 95,000 square feet across six floors. The project’s non-identical twin, also for the Crown Estate, sits across the road on the other side of New Burlington Street.