A watching brief was held during the excavation of a trench for a new gas main which was dug from south to north running from Cowdray Crescent through the Castle Park and into the east side of the Castle. The trench was comparatively shallow, averaging 0.8m deep and 0.45m wide. The first part of the trench by the Castle Park gates was observed by Denis Gamble (Colchester Borough Council engineer) who reported nothing of significance showing in the sides. Possible natural sand was observed at a depth of 0.5m approximately 12.5to 14m from the wall by the gates and this may indicate the western limit of the Bailey ditch. Elsewhere the trench fill was uniformly a mixed topsoil layer of possible post-medieval date. The stretch of pipe trench cutting the path up to the south-west corner of the castle consisted largely of modern make-up with fine greyish brown sandy loam with layers of brick rubble and some sand. Further north the trench cut a thin layer of 'dark earth' in places reaching natural sand. A large medieval? pit, or possibly a robber trench, cut natural sand. The short east-west length of pipe trench leading to the castle was only 0.5m deep and consisted solely of topsoil.<1>