21, Arlington Street SW1

No. 21 Arlington Street is a town mansion built in 1738 by G. Leoni for the 2nd Viscount Shannon. It underwent repairs and alterations by Chambers for the 3rd Viscount Weymouth in 1769, with further changes to the facade in the mid-19th century. The building features brown brick with stone dressings and a slate roof, rising three storeys with a basement and two tiers of dormers in a mansard style. It is four windows wide, with the entrance located in the second bay from the right. The entrance has a semi-circular arched doorway with a sculpted keystone and a patterned fanlight, set within an enclosed stone porch supported by Ionic columns, featuring a pulvinated frieze and a bracketed cornice. The sash windows, which have no glazing bars, are recessed in stone architraves, with those on the first floor adorned with consoles and pediments. The building includes a first-floor plat band and a sill band, as well as a stone cornice below the parapet with coping. Wrought iron area railings return up the steps to the porch and include lampholders. The interiors retain elements from the 1740s, such as a large chimney piece in the Kent manner and doorcases, along with rich stucco work in the stair compartment and a coffered ceiling.