It is not a castle, however, but a belvedere, a decorative viewing structure built purely to frame a prospect. The distinction matters: where a castle was built for defence, a belvedere was built for pleasure, a folly of sorts designed to satisfy the Georgian and Regency taste for composed landscapes, dramatic outlooks, and the theatre of wild coastline made legible from a safe, elevated vantage.

The tower measures about 3.5 metres east to west, with a first-floor doorway set into the north wall and hood mouldings, small projecting drip-stones above window openings that deflect rainwater, decorating the third-floor windows. These details suggest a building that was meant to be read as architecture, not just built for function. By 1842, when the Ordnance Survey produced its first six-inch mapping of the area, the structure was already recorded simply as 'Tower', suggesting it was a known feature of the local landscape rather than something newly built. A broadly similar tower stands visible to the north-east, likely constructed somewhat later, which points to a pattern of deliberate landscape design across the Rock Island promontory rather than a single isolated whim.