This is the first in a short series of posts about hidden or obscure features from the early years of Cavendish Square, a place that has more than its share of surprises for those with an interest in eighteenth-century architectural and art history.
Cavendish Square was laid out in 1717–18 with palatial aristocratic habitation a primary intention. As landowners, the Harley family sought to capitalize on top-echelon contacts to give development of its Marylebone estate the lustre of wealth. Plans were set tolerably fair, but went awry with the bursting of the South Sea Bubble in 1720. Money vanished and so did most of the aristocrats. By 1730 only two aristocratic town houses had been completed; one (Bingley House, to the west) has wholly gone, the other survives in forgotten part at the south end of the square’s east side, as No. 1a or Flanders House, where the Flemish representation of the Belgian Embassy has been housed since 2003.
This building is the southern third of what went up in almost cubic form in 1720–6 as Harcourt House, for Simon Harcourt, 1st Viscount Harcourt and a former Tory Lord Chancellor, who, suffering cataracts, was all but blind. This fact as much as short money might explain why richly Baroque first designs by Thomas Archer  were pared down by Harcourt’s first executant architect, Edward Wilcox; he died and in 1721 was succeeded by Francis Smith of Warwick. In 1724 Harcourt was three months a widower before marrying Elizabeth, née Vernon, the widow of a former friend, Sir John Walter. Lavish furnishing of the house, including Genoese damasks patterned with leopards, suns and elephants, was attributed to her influence. The internal fit-out was overseen by George I’s cabinet-maker James Moore. Harcourt did not enjoy the house long, dying in 1727.
His grandson, Simon, 1st Earl Harcourt, enlarged a middle back parlour with a canted bay in 1758 and gave it an interior by James ‘Athenian’ Stuart. This was Stuart’s first London commission and an important early ‘Greek’ neoclassical work. It was not universally liked – ‘God Damn my Blood My Lord is this your Grecian Architecture what villainy what absurdity If this be Grecian, Give me Chinese give me Gothick, Any thing is better than this, For Shame My Lord Pull it down & Burn it . . . not to expose your own ignorance for it is the most Wretched miserable affair ever was seen by Mortal.’  This round deprecation by Lord Delaware was famously relished by Robert Adam and Paul Sandby. The more stolid Stiff Leadbetter was responsible for plainer alterations in the early 1760s, including the addition of a room to the south-east along Margaret Street.
The house was divided into two dwellings in 1825–7 and remodelled with new stucco facing by Sir Jeffry Wyatville. Sir Claude Scott, who had made a fortune as a wartime government grain contractor, bought the southern section and enlarged the Margaret Street room to be a banking hall, which, extended again in 1873, survives as a NatWest branch. Further works in 1928 that were overseen by Wimperis, Simpson and Guthrie gave the surviving part of the building its current appearance. The last aristocrats departed from the five-bay northern dwelling during the First World War. In came Queen Mary’s Needlework Guild and then, in the 1920s, the Mixed Arbitral Tribunals set up by the Treaty of Versailles to settle disputes arising from the war. Demolition and replacement with an explicitly commercial building followed in 1933–4.
- In the British Library – King’s Maps xxvii.6
- As quoted by Richard Hewlings in ed. Susan W. Soros, James ‘Athenian’ Stuart 1713–1788: the rediscovery of antiquity, 2006, pp.195–7