A watching brief was held during the excavation of a trench for a new gas main along Trinity Street and Sir Isaacs Walk. The trench was about 0.6m deep. Its southern part cut through what appeared to be the remains of at least one building, i.e. a foundation, floor (s) and a ?pila stack presumably in situ in a hypocaust. The soil within the trench in Sir Isaacs Walk contained a high proportion of yellowish brown sandy loam and gravel which was probably backfill from the Roman rampart behind the town wall.<1>