Placed to provide a 'leading line' with the Upper (Pharos) Light, to guide ships into the harbour channel at night. Almost certainly designed by Decimus Burton, it was built from red sandstone at a cost of £1000. The structure has three stages. The lower stage has columns on a two-step podium, forming a portico on the south side. It also has a balustrade with vase-shaped balusters, dies, and moulded rail. The middle stage has one blind round-arched door with plain raised frames on each side, each with an oculus above. It also has a balcony with cast-iron railings. The octagonal top stage has a moulded cornice and octagonal dome with tiny octagonal drum at its apex.