26, St James'S Place

Block of eight luxury flats, built 1959–60, designed by Denys Lasdun and Partners with Alexander Redhouse as partner in charge; Graham Lane, Lyall Anderson and Maya Hambly were assistant architects. Ove Arup and Partners served as engineers.

The building employs a reinforced concrete structure clad with Baveno grey granite, with white vitreous mosaic applied to the soffits. Window subframes are made from pressed grain-blasted bronze sections, and external ducts are faced with blue engineering bricks.

The rectangular site plan accommodates three storeys of smaller rooms on the north side set against two floors of high-ceiling living rooms at the corner overlooking the park. The building contains a basement garage and caretaker's flat, one small flat with garden at ground floor level, and main accommodation consisting of four large and two smaller flats distributed across the first to sixth floors, with a penthouse flat above featuring its own roof garden. The four large flats employ split-level planning, while the smaller flats are arranged on a single level only.

The structure is supported on a concrete service core, with floor slabs and posts positioned centrally on each elevation and expressed externally. On the park front, the split levels are expressed through bands of granite with a set-back vertical divide between the south-west corner section, which has higher floor heights. Cantilevered balconies feature thin metal balustrades. The side elevation uses brick to denote the vertical distinction between higher and lower areas. The entrance front of six storeys is marked by bay granite bands. Windows are vertically set with set-back weatherings on the right-hand side; on the left, horizontally set windows partially divide the ground floor entrance. The penthouse sits set back behind a terrace with board-marked finish and cantilevered roof slab. All windows are double-glazed.

The interiors are spatially complex but designed for maximum flexibility in services planning. The main staircase and those within the larger flats are cantilevered with open treads.

The building was constructed on the site of two Georgian houses destroyed during the War. The design aimed, as stated in Architectural Design in November 1961, "to produce a building of our time which would, in terms of urban renewal, concern itself with the relationship between buildings of historic interest and modern architecture." It forms a spectacular group with the adjoining grade I Spencer House, contrasting yet sympathetic in character. Ian Nairn wrote in the Architects' Journal of 29 June 1961 that it was "a triumphant justification of putting completely modern buildings right next to the eighteenth century. It is a real tour-de-force and only a very few British architects could have brought it off."

The design reflects Denys Lasdun's wider ideas on "grain" and city planning. While at the opposite end of the market from his earlier Claredale Street flats (of which Keeling House is already listed), both share the principle of retaining existing urban character while introducing thoroughly modern design. The 3:2 split-level plan derives from Melnikov, and in Britain from Wells Coates's No. 10 Palace Gate, on which Lasdun had worked as an assistant. Lasdun had also worked with Berthold Lubetkin, whose 2:1 plan for Highpoint II represented a less sophisticated method of gaining extra space in luxury accommodation.

The building was awarded the RIBA London Architecture Bronze Medal for 1960. Sir Philip Powell praised it in the Architects' Journal of 15 January 1964 as "a building which does not look mean in scale when compared with its spacious neighbours. A fine abstracted composition which, nevertheless, answers and expresses the requirements of the way the building should work."

No. 26 St James's Place is significant as Lasdun's first mature work, in which the balance of contrasting planes and strong horizontals that characterise his architectural language achieve a cohesion and confidence, enhanced here by the exceptional materials available.