A trench dug to replace the water mains on Trinity Street and King's Parade provided the opportunity to record the archaeological deposits that were revealed. This report concerns the first 50 metres of the trench from the south end of Trinity Street to opposite the entrance to St. Mary's church. A deep sequence of road surfaces was revealed in Trinity Street with seven or more gravel surfaces interspersed with layers of debris accumulated during periods of use. Along King's Parade the pipe trench cut through the foundations and cellar walls of at least five cellars associated with the houses on the west side of the street that were demolished to build Senate House in the 17th/18th centuries. The cellars were infilled at the time of demolition. In the gaps between the cellar walls parts of an earlier sequence of floors, surfaces, gullies and pits had survived. This sequence shows that the road side was built up from at least the 13th century, while a stray find of Saxo-Norman pottery suggests earlier activity.