Fox's Wood Tunnel West Portal (MLN111622)

Fox's Wood Tunnel West Portal is a Grade II* listed structure made of squared and coursed Pennant stone, featuring dressings of Pennant ashlar for the voussoirs and capping stones. The portal has an asymmetric design, characterized by a semi-circular arch with stilted voussoirs and a stepped section that includes a chamfer. It is flanked by two towers of differing height and shape.

The north tower, which is circular, rises from a spurred square base and has an upper section that steps out to create a parapet with crenellations, topped with moulded capping stones. Attached to this tower is a curved retaining wall that steps down. The parapet of the north tower continues without crenellations over the central arch and features 20th-century railings. The south tower is rectangular in plan and slightly taller, but is otherwise treated similarly to the north tower. This tower abuts a cliff of rock outcrops to the south, which is reinforced with massive buttresses.

The portal is located at the eastern end of a short stretch of railway line that runs along a shelf between a steep hillside and the River Avon, which was diverted by Isambard Kingdom Brunel.