In 1236/7 the City of London was granted permission to tap the Tyburn Springs, at about where Stratford Place now is. Work to build the conduit began in 1245. it went via Piccadilly, Charing Cross, the Strand, Fleet Street, Ludgate Circus, north of St Pauls, to Cheapside. At the site of the plaque there was a a deep cistern and fountain.
At Ancestreemakers we learn that the conduit was "a wood and lead water pipe with an internal diameter of 90 mm, which lay, encased in clay, at the bottom of a deep trench". Already being superseded by other sources of fresh water the conduit was damaged in the Great Fire and abandoned.
The image shows the Conduit to the right, and comes via The Guardian from Guildhall Library & Art Gallery/Heritage Images/Getty.
