No.20 and Attached Railings

No. 20 and its attached railings are a pair of two houses, now converted into flats, dating from 1808. They were designed by John Pinch the Elder and are part of the Park Street development. The front facades are constructed from limestone ashlar, while the rear incorporates limestone ashlar and rubble. The roof is hidden behind a parapet, and the party walls are coped with brick and ashlar stacks to the left of each house.

Each house has four storeys and a basement, with a three-window front range. The first floor on the left side features three 19th-century plate glass windows with two-over-two sashes and wrought iron balconettes mirroring those found at No. 19 Park Street. The first floor to the right has three six-over-nine-pane sashes and similar balconettes. The second floor has three plate glass sashes; the third floor on the right has three matching windows. The ground floor to the left also has three plate glass sashes. The window to the right of the ground floor was formerly the doorway. To the right, a six-panel door features reeded and raised panels, a decorative fanlight with crown glass, and a single step to a pennant paved crossover with a cast iron footscraper. All basement openings have been blocked with ashlar, and the crossover and area steps to the former house on the left have been removed. Architectural details include band courses over the ground floors functioning as sill bands for the first-floor windows, sill bands to the second floors, friezes, moulded cornices over the second floors, moulded eaves cornices, and coped parapets. A wrought iron lampholder is positioned above the front door. Windows to the rear elevation are 19th century, except for the ground floor and the second-floor half-landing of the house on the right. The interior has not been inspected.

Attached to the front are wrought iron railings with shaped tops set on limestone bases. These houses are part of the incomplete St James's Square development, initially based on land leased from Sir Peter Rivers Gay in 1790. Upper Park Street was designed by John Palmer and later continued by John Pinch after 1808 but was not completed as originally planned, and the street formerly ended at All Saints Chapel.