The drawing, taken from Chamberlin, Powell and Bon’s 1959 Scheme, shows the route of the existing sewer system, and the proposed route of new sewers for the estate, in relation to the new Barbican estate buildings. The scheme involved lowering the site. Much of the Barbican estate, including open areas such as the lake, and gardens, as well as mews houses and garden flats, are below street level. But when the Corporation of London surveyed the site before commencing construction, they discovered it contained 8,000 feet of sewers belonging to the Corporation and a further 1,300 belonging to the London County Council.

The development would expose 1,600 feet of branch sewers which had to be removed. There were a further 2,290 feet of redundant sewers less than four feet below the new surface which also went. There were a further 1,495 feet of redundant sewers at an average depth of 17 feet below the new ground level, which were left in place. But they were filled with gravel and walled up at 20 foot intervals.

Two main sewers from pre-War times were to be retained. One was a London County Council main sewer which ran under Redcross Street and Fore Street – essentially the route from Frobisher Crescent under the lake and then under Andrewes House to Fore Street. This was left in place for continued use. It was very deep. In fact, it was below the existing railway and the new railway line was also built above it.

The second retained sewer was the Jewin Street sewer. Jewin Street was one of the historic streets which ceased to exist when the Barbican was built. Jewin Street ran from Aldersgate Street (near the position of the London Museum) to just north of St Giles’ church where it met Redcross Street. So the sewer now runs under Thomas More House. (Jewin Street took its name from the fact that this part of the City was a Jewish banking quarter in the early Middle Ages).