Colchester Archaeological Trust carried out a watching brief at the Sixth Form College during the construction of a new computer block (the ‘north site’, a single storey computer block 30 x 35m) (CBC planning application F/COL/00/1761). Groundworks in the northern part of the site did not extend deep enough to impact archaeological remains. The new computer block was constructed using piles and no pile caps. Ground-beams were dug to within 1m of finished ground-levels in order to keep any damage to archaeological remains to a minimum. Drains were dug to no deeper than 1.4m below finished ground-level. The one service trench monitored was dug to a depth of 1.4m and archaeological levels were not reached. However, at the southernmost end of the site of the computer block, an area of tarmac path was cut into to a depth of 1.2m, to level out the slope. A layer of demolition debris containing painted wall-plaster from a Roman building was recorded, starting at 700mm below the level of the tarmac path. Adjacent to this layer, a robbed-out wall deriving from a Roman building was observed, just below the level of the tarmac path. A pit containing animal bones may represent the remains of post-medieval leather production. <1>