Two retired Wall Street investment bankers are behind the restoration of this remarkable Grade II* listed building, since acquiring No 16 and two other houses in the Square in 2003. The Cherren Group was founded by Andrew Osinski and Jack Jacobs in 1996.

This grand Georgian centrepiece of the area know as Fitzrovia was developed by Charles Fitzroy, later Lord Southampton. Robert Adam designed the east and south sides shortly before his death in 1792, and the north and west were added in 1825-29. The parties to No 16’s building lease of 1827 were Lord Southampton and Joshua Mayhew of Chancery Lane. From 1863 to 1879 the six-storey house was occupied by the distinguished surgeon and inventor Charles Brooke. It became an exalted neighbourhood: the prime minister Lord Salisbury lived at No 21 and Ford Madox Brown at No 37, while No 29 was home first to George Bernard Shaw and then to Virginia Woolf.

Previously occupied by the charity SCOPE, No 16 has been painstakingly restored. Original features that have survived include the staircase and some good plasterwork concealed behind suspended ceilings. According to the Georgian Group, whose offices are at No 6, the most remarkable feature is the first-floor passage, where the decoration has obvious parallels with that in Sir John Soane’s House of Lords, completed in 1824, but now demolished.

The accommodation of 6,376sq ft includes five reception rooms, six-bedrooms, four bathrooms and a kitchen. The 24ft south-facing drawing room on the first floor has French windows overlooking the circular garden of the square, which is now partly pedestrianised. Next door, restoration has begun on No 17, with the freehold for No 16 being offered at £3.95 million, if you can stand all that dust and noise.