This report details observations made during a watching brief on the trenching for a new relief drain running from St. Margaret's Mews to the Priors gate within the Precinct of Rochester Cathedral. Three phases of activity were identified. The earliest features were a number of pits of probable Roman or Anglo Saxon date. Towards the western end of the trench, a fragment of the foundations of the medieval town wall was recorded. Above this and recorded along the entire length of the trench were a series of postmedieval levelling layers interspersed with patches of flint cobbled surfaces.