From the Historic England entry:
“1-4 Argyll Street. Formerly known as Ideal House.
Corner office block. 1928-9 by Raymond Hood in collaboration with Gordon Jeeves, extended northwards in 1935. Polished black granite facing, metal casement windows, enamel trimmings; flat roof not visible. 7 storeys with a recessed attic storey. 7 windows wide on upper floors to Great Marlborough Street, 11 windows to Argyll Street where they are arranged in spaced groups of 4 and 7 bays, reflecting two phases of construction. Ground floor with large flat arched display windows and doorways pierced without moulding but emphasised by inlaid frame of bronze champlev enamelled plates in formalised lotus and jazz-moderne geometric patterns in a range of yellows and oranges, greens and gold. Plain openings with metal casements to upper floors. The champlev motifs appear again as a frieze pierced by the 6th floor windows and reappear on the stepped and coved main cornice and similarly coved attic cornice, each of Egyptian inspiration.
INTERIOR: not inspected. HISTORY: this building was constructed for the National Radiator Company, and was a reduced version of the American Radiator Building on Bryant Park, Manhattan, the New York premises of the National Radiator Corporation by Raymond Hood, the parent company of the English firm. The black and gold colours reflect the livery of the company. It comprised a ground floor show room with lettable offices above. Originally the building comprised the southernmost four bays, but was extended by a further seven bays to the north in 1935. A very unusual instance of a London-scaled American tower block design, embellished with the sort of Art Deco or ‘Moderne’ details in fashion following the Paris Exhibition of 1925. This is the only European building of Raymond Hood, described by A. Saint as the ‘wittiest and most thoughtful of the inter-war New York skyscraper architects’. The enamel surround to the Argyll Street entrance was removed and is now in the Victoria & Albert Museum.”