20 and 21, St James's Square SW1

Nos 20 and 21 St James's Square are terraced townhouses located in Westminster. No 20 was built between 1771 and 1775 by the architect Robert Adam for Sir Watkin Williams Wynn. No 21 was carefully rebuilt in 1936 by Mewls and Davis to match the facade of No 20, creating a cohesive appearance. The buildings are constructed of Portland stone with a slate roof, featuring four storeys, a basement, and stone dormers added in the 1936 renovation. The facade is seven windows wide, with a rusticated ground floor that includes semicircular arched openings for windows and doors at either end, which have sidelights and delicately patterned fanlights. The glazing bar sash windows on the first and second floors are square-headed, with those on the piano nobile set within semicircular arched panels topped with consoled pediments. These are framed by a giant order of fluted Corinthian pilasters supporting a main entablature with a frieze of Paterae. The attic storey, added in 1936, features a dentil cornice and a balustraded parapet. An enriched plat band runs along the second floor between the giant pilasters, and there are cast iron area railings. The rear elevation includes a bow and a wing on the north side of the courtyard. The interior of No 20 is remarkably well preserved, showcasing a grand staircase with a copper balustrade made of openwork balusters, a top-lit oblong well, a former Eating Room and Music Room on the ground floor, and drawing rooms on the first floor, all retaining original plasterwork, paintings by Zucchi, mahogany doors, and door furniture.