Conduit Head At One Tree Hill, Greenwich Park

Conduit Head at One Tree Hill, Greenwich Park

This late 17th or early 18th-century structure is a conduit head, possibly designed by Nicholas Hawksmoor, who served as Clerk of the Works at Greenwich from 1698 to 1735. Built in the Classical style, it is constructed of yellow and red brick with stone dressings.

The building has a distinctive semi-circular plan, set into sloping ground. It originally served as the entrance to a conduit that ran north to south beneath One Tree Hill but is now blocked. The structure comprises a central block flanked by curving arms that slope downward to ground level.

The central block measures 2.2 metres high and 2.2 metres wide, built in yellow brick laid in Flemish bond with red brick quoins and arch voussoirs. A central round-headed arch, 1.35 metres high and 0.75 metres wide, features a stone keystone and three additional stone quoins. A stone band incorporates the keystone, and flat stone coping runs across the top. Above the arch sits a stone plaque bearing an inscription that is now illegible. The arched opening was blocked with red brick in header bond during the 1980s or 1990s using reused bricks. The arms are constructed of yellow brick in Flemish bond, butt-jointed to the central block in a manner suggesting they are later additions, though still dating to the 18th century. These arms have a 20th-century concrete coping. Alongside the stone coping, the curved brick roof of the conduit can be glimpsed, though the conduit is now inaccessible. A record from 1902 documented that a branch ran eastwards towards Maze Hill.

The entrance has been blocked in brick and remains inaccessible. The conduits beneath are not included in the listing.

At least three underground brick-built conduits or tunnels exist beneath Greenwich Park, constructed large enough for a person to walk upright. These were water mains designed to channel natural groundwater from the higher parts of the hill to the buildings of the Royal Hospital for Seamen (now the National Maritime Museum), a Grade I listed structure. Construction of the Royal Hospital began in 1696 during the reign of William and Mary, using an uncompleted building from 1664 originally intended as a palace, designed by Sir Christopher Wren. The hospital opened in 1705, though it was not fully completed until later in the century. According to Pevsner's Buildings of England, Nicholas Hawksmoor, Wren's pupil, had special responsibility for conduits. Following his appointment as Clerk of Works at Greenwich in 1698, he held the position until 1735 and served as Deputy Surveyor between 1705 and 1729. The surviving conduits were rebuilt at the end of the 17th century, though earlier conduits serving the Tudor palace or medieval manor houses may have been reused by naval engineers. Lead pipes conveyed water to reservoirs at the end of the conduit systems. The 18th and 19th centuries saw the conduit system decline, with several abandoned as early as 1732. An 1831 report recommended an improved water supply for the Royal Hospital through new reservoirs and replacement of lead pipes with iron. A new reservoir was constructed in Greenwich Park by Great Cross Avenue in 1845. In 1905 and 1906, Greenwich Borough Council inspected these conduit structures and produced reports. Following this, known entrances to the conduits were sealed by the Royal Parks authority to prevent unauthorised access. Three conduit heads or houses are known to have served the Royal Hospital for Seamen: one at Hyde Vale, the Conduit House at Standard Reservoir, and this One Tree Hill Conduit Head, all of which are listed.