It was designed by James Stuart, though largely the work of Benjamin and Philip Wyatt, who re-modelled it for the 3rd Marquess of Londonderry, 1825-28.
It remained in the family’s ownership until 1962, when it was sold to Hilton Hotels and subsequently demolished.
More than two centuries ago the southern end of Park Lane formed part of the Brookfield estate of the Curzons.
In the early 1760s, when Hertford Street was laid out, the 4th Earl of Holderness obtained a plot at its west end, and on the corner site built a house.
When he died in 1778, his widow continued in occupation until her death, in 1801, when the lease was taken over by the 6th Lord Middleton.
Originally there was no entrance to the House from Park Lane; it was in Hertford Street, separated from its neighbour by a fair-sized garden.
Soon afterwards, the garden was built on and Holderness House was re-numbered as 25 in the street.
When, in 1822, the 3rd Marquess of Londonderry bought Holderness House, he bought with it the newer house to the east, and, having acquired the freehold as well, he proceeded to join the two houses together and to reconstruct both, greatly enlarging them in the process.
The exterior was stuccoed and re-designed, and an entrance was formed in Park Lane at the south end of Holderness House, where there was once a narrow lane.
The 3rd Marquess was half-brother of Robert, the celebrated Lord Castlereagh.
Castlereagh never lived at Londonderry House: his town residence was at 18 St James's Square.
The re-modelling of Holderness House began in 1825.
In August, 1828, it was opened with a splendid fete and ball, and at once took its place among the great mansions of London, where for over forty years Lady Londonderry entertained magnificently as one of the principal Conservative Party hostesses.
Though the house had undergone subsequent alterations, particularly on the ground floor, a considerable amount of Wyatt's and Athenian Stuart's work remained.
Entering from Park Lane was the vestibule with a chimney-piece framing a painting of Seaham Harbour.
Several steps up, one entered the staircase hall, beyond which was a wing added in 1825 to accommodate the Banqueting Hall and Ballroom over it.
The statuary at the foot of the staircase included Canova's Theseus and the Minotaur and portrait busts of Pitt and Castlereagh.
The staircase, with its double-returned flights, was framed with pairs of columns.
It was top-lit by a clerestory, rising above coffered coves, with the openings divided by Atlas figures supporting the roof.
A gallery ran round all four sides at first floor level, with columned features opening into the ballroom and the ante-drawing-room on the south and north sides.
The north end of the drawing-room faced the whole of the first floor overlooking Park Lane.
This room had no fewer than nine portraits by Lawrence, including two of Castlereagh and two of his brother.
At one end of the ballroom (above) hanged a full-length portrait of Castlereagh in his Garter robes, which he wore at the Coronation of GEORGE IV.
This was a contemporary copy by Lawrence of the picture at Mount Stewart in County Down.
On the north side of the ballroom, over and flanking the fireplace, hanged portraits of Czars ALEXANDER I, NICHOLAS I, and ALEXANDER II.
Opposite the Czars hanged portraits of GEORGE IV, the Duke of Wellington and the 3rd Marquess of Londonderry.
Opening off the far end of the room was a conservatory, built on a bridge connecting the ballroom wing with the Hertford Street front.
Of the ground-floor rooms, the dining-room, facing Hertford Street, was probably the entrance hall of the original Holderness House.
The banqueting hall (above), below the ballroom, was elaborately decorated in LOUIS XV style.
The library was on the Park Lane front, reached from the foot of the staircase; at the opposite end of which Stubbs's great picture of Hambletonian hanged.
A series of statuettes, some rather grotesque, stood on Lord Londonderry's writing-table, caricaturing such figures as Wellington, Talleyrand, Rogers, Sefton, D'Orsay, Eldon, and Brougham.
They had been discovered at Mount Stewart.
Charles Villiers, a grandson of the late Lady Mairi Bury and great-grandson of the 7th Marquess and Marchioness of Londonderry, has kindly provided me with the above documents and images.
First published in December, 2011.