Powis House and the Trevor Estate
Trevor Square and Trevor Street were laid out on the site
of Powis House, a late-seventeenth-century mansion
belonging to the Trevor family of Brynkinalt in Denbighshire, but named after an eighteenth-century occupant, the 1st Earl of Powis. Standing a little way back from
the Kensington road, Powis House was probably built in
the late 1680s. The first ratepayer, in 1690, was the 2nd
Earl of Peterborough, the Royalist and Catholic convert
(who spent most of 1690 in the Tower). His successor there
in 1691 was William of Orange's right-hand man, William
Bentinck, 1st Earl of Portland. By 1700 the house was
in the occupation of another prominent Whig, Lord
Haversham. The residence there of Sir John Trevor
(1637/8–1717), the politically corrupt Master of the Rolls,
began about 1704. (ref. 1) Sir John also had a house in Clement's
Lane in the City, where he died, as well as his Welsh seat.
The architect W. W. Pocock (whose father oversaw the
development of the Trevor estate) described Powis House
as 'widespread rather than lofty', built of plain brick, with
a central doorway and wings on either side containing
offices. His description, based on a drawing he had once
seen, tallies more or less with the rear view of the house
depicted on Rhodes's map of 1766 (Plate 2a). Though plain
externally, it was evidently well fitted up inside, for Pocock
recalled his father showing him some marble chimneypieces which he had had made from the 'handrails' of
the main staircase. (ref. 2)
Powis House occupied part of what had once been the
estate of Sir William Blake, who at his death in 1630 owned
extensive property in and around Kensington and Chelsea.
For some years, Sir John Trevor appears to have rented the
place from a descendant of Blake, Anna Maria Browne, but
he later obtained the freehold – probably about 1715, when
he acquired some adjacent property (including the future
site of Smith & Baber's floorcloth factory) from Anna
Maria and her second husband John Thurloe Brace. (ref. 3)
Prudentia Trevor, Sir John's spinster daughter, kept the
house after her father's death, living there and in Golden
Square. She also obtained more property near by, including about an acre of partly built-up ground east of Powis
House and separated from it by a narrow strip of ground
not belonging to her. (ref. 4) At the time of her death in 1739,
therefore, she owned two nearly conterminous freeholds in
Knightsbridge; together they amounted to over six acres
(see fig. 21 on page 78). The development of the smaller,
eastern, portion of the estate (now covered by part of Mercury House) is described in Chapter IV.
Prudentia Trevor bequeathed the Knightsbridge property to her brother Arthur, who died in 1758 leaving it to
his nephew Arthur Hill (later Viscount Dungannon), who
took the additional name of Trevor. (ref. 5) He died in 1771, and
it was his grandson Arthur Hill-Trevor, 2nd Viscount
Dungannon (1763–1837), who initiated the development
of the ground. Following the death of his son, the 3rd Viscount, in 1862, the estate was inherited by Lord Arthur
Hill, who took the additional name of Trevor by royal
licence and was made Baron Trevor of Brynkinalt in
1880. (ref. 6) His son, the 2nd Baron, was the last member of the
Hill-Trevor family to hold the land, which was sold in 1909
to the Knightsbridge iron-buildings manufacturer and
property developer, James Charlton Humphreys.
Following Arthur Trevor's death, Powis House was let
to a succession of tenants, among them George II's mistress, the Countess of Yarmouth, who lived there for a
while after the king's death before returning to her native
Germany. The 1st Earl of Powis, a former Comptroller and
Treasurer of the Household, after whom the house was
named, resided there for several years from the late 1760s.
In the 1780s and '90s, Powis House was occupied by
Thomas Harris, the proprietor and manager of Covent
Garden Theatre, who, in collaboration with R. B. Sheridan
and others, planned in the early 1780s to build a theatre or
opera house near by, on the Lowndes estate, east of Sloane
Street. Henry Holland was to have been the architect, but
the scheme was ultimately abandoned. (ref. 7) Harris reportedly
lost a collection of manuscript plays when in 1794 the fire
which destroyed the floorcloth factory next door to Powis
House spread to his outbuildings. (ref. 8)
Figure 28:
Trevor Square area in the mid-1860s: Trevor Terrace is shown with post-1903 (Knightsbridge) numbers. The development of the detached portion of the Trevor Estate is described in Chapter IV
By this time, however, the building of the Life Guards
barracks immediately opposite Powis House had spoiled
both the view of Hyde Park and much of the sylvan charm
of the locality. Within a few years, it was decided to pull
down the old mansion. The last occupant, who lived there
from 1801 until 1810, was a John Bruce, possibly the historian and keeper of the State Paper Office. (ref. 9)
(fn. a)
Adjoining Powis House on the east (being perhaps part
of the original building, or built on the site of a service
wing) was a house once occupied by a celebrated dentist,
John March, who died there in 1802. Born in Sweden,
March served as a French army officer before taking up his
profession. As dentist to the nobility, he was said to have
taken higher fees than had ever been charged before, but he
also gave free treatment to artists and others of lesser
means. (ref. 11)