Flat Holm Lighthouse

Flat Holm Lighthouse is a 30-meter tall tapering circular tower made of white painted lined-out render over rubble, set on an octagonal base that is mostly surrounded by service accommodation. The tower features a plain moulded band just below its top and a strongly projecting moulded cornice that supports a railed platform around the lantern. The lantern has a ribbed cast-iron base that houses the service room and is fitted with lattice glazing, topped by a drum-cowl and an arrow weather vane. There are narrow stair windows aligned above the entrances to the tower, along with a single rectangular splayed window in the upper stage.

The single-storey building that encloses the tower has an original doorway on the sea-ward side that is now blocked. It features a chamfered 4-centred archway flanked by narrow side-lights, with the Trinity House arms in a chamfered pedimented centre-piece of the parapet. The flanking ranges are symmetrically arranged and have renewed fenestration. A projecting porch on the north-facing elevation may be a later addition or modification. It is believed that these buildings were originally constructed around 1820, although they have been added to and altered in more recent times. The lighthouse is surrounded by low rendered rubble walls.

Inside, the tower is open to its upper stage and contains a cantilevered spiral stone stair with a cast-iron rail. There are ornate cast-iron brackets supporting the lantern walkway and a short spiral access stair. The lighthouse is equipped with a helical 'beehive' lens that includes red sector lights.