33 Margaret Street is a commercial development amalgamating three prominent sites in central London - 289-293 Regent Street which is also known as Marcol House, 295 Regent Street and 33 Margaret Street. The scheme involves the retention of the façade of Marcol House and 295 Regent Street and the introduction of a new building element on the site of 33 Margaret Street. The proposal will create seven floors of commercial office space with a gross area of 13,500 m2. The historic context called for a sensitive response that balanced the retention of listed façades with the requirements of modern office accommodation. There is a clear distinction between the new and retained elements, expressed by a frameless vertical glazed slot on the junction of Marcol House and 33 Margaret Street. While creating a material homogeneity with the existing urban context, the treatment of the stone planar walls is entirely contemporary. Equally, while the new mansard roof faithfully responds to the re-instated mansard roof through alignment and colouration it is actually a modern zinc-clad interpretation of its traditional counterpart. The building will achieve a BREEAM ‘Excellent’ rating and provide enhanced site biodiversity through the introduction of a living green roof.