A large lump of collapsed masonry (in several pieces) is located immediately to the south of Duncan's Gate, and in line with the gateway. This has been interpreted as the remains of a gate tower or turret that has fallen and been preserved in situ adjacent to the gate, and on the line of the carriageway; Duncan, however, referred to this as the fallen arch of the gate. It consists of the outer face of the south wall of the tower, above the main archway and comprises over 30 courses of tiles. The masonry includes evidence for two tile window arches.<1><2><3> Hull proposed two possible interpretations/reconstructions, one a tower with three windows and the other with two.<2>

Following investigation by the Colchester Excavation Committee in 1927-9, the remains were restored/consolidated.<3> In advance of conservation in 2016, a Historic England Level 3 analytical survey was carried out (following decay and collapse).<3>