An archaeological evaluation, monitoring and recording was carried out at the former Essex County Council Offices (Altnacealgach House), Park Road, Colchester in advance of and during the conversion and extension of the existing house into residential apartments, the construction of a gatehouse dwelling and associated access, car parking, landscaping and related works (CBC application 135948). No significant archaeological features or horizons were present.<1> A single trial-trench (T1), 10m long x 1.8m wide, was excavated within the footprint of the new gatehouse. It was excavated to a depth of 700-900mm below current ground level. Four layers were identified. At the east end of the evaluation trench was a layer of redeposited natural possibly associated with current groundworks (L1, c.120mm thick). Where present, L1 sealed L2. Modern sandy-silty topsoil (L2, c.320-500mm thick) sealed an accumulation horizon of medium grey/brown silt (L3, c.270-300mm thick, containing fragments of medieval/post-medieval peg-tile that were not retained), which sealed natural sand (L4, identified at a depth of approximately 700-900mm bcgl). The area of the new car park was reduced by 500-600mm through modern topsoil (L2, 350-400mm thick) and onto an accumulation horizon of medium grey/brown silt (L3), under archaeological supervision. Natural ground level was not exposed during this strip, located approximately 200-300mm further down. The service trenches measured 0.5m wide by 1-1.2m deep and were excavated through tarmac and crush (L5, c.200-220mm thick) onto modern topsoil (L2, c.150mm) and an accumulation horizon of medium grey/brown silt (L3, c.380-450mm thick) which sealed natural sand (L4). Two extensions were made to Altnacealgach House. These were due to be monitored but unfortunately this was overlooked by the contractors on the ground.