1 And 3, Riding House Street W1

Nos 1 and 3 Riding House Street is an office block designed as the Radium Institute, noted as the first institution of its kind in England. It was built in 1911 by architect Thomas Phillips Figgis. The original western pavilion was extended in 1931 with a linking range to create an identical eastern pavilion. This stone-faced building features vigorous Baroque detailing and green Westmorland slate pyramidal roofs. The structure consists of twin pavilions, each three windows wide, connected by a simpler recessed three-window range. It has a basement, four main storeys, an attic, and a dormered roof for each pavilion. The basement and ground floor are characterized by boldly channelled rustication, which supports channelled quoins adorned with cartouches. The building also features a swagged frieze and a deep modillion cornice, along with good mosaic wall tiling in the corridors. It is listed for its historic and architectural significance.