1. Bardsey Island Lighthouse is significant for having the tallest square tower of any lighthouse site in the British Isles. It is set on the southern tip of Bardsey Island off the Llyn Peninsula and marks the division between Caernarfon and Cardigan Bays. The tower is built of ashlar limestone unplastered inside and out, but painted externally with white and red bands; the stone was supplied by William Thomas. The tower retains its original gallery railings, which are of iron and bellied (i.e. curved out in width at their centres) towards the top. The tower has an elaborately enriched plinth about 4m (13ft) high. At ground level the structure is 7.6m (25ft) square reducing to 6.1m (20ft) at the top of the plinth and to 4.6m (15ft) at the summit of the tower below the crowning cornice which is itself 5.5m (18ft) square. The walls are 1.2m (4ft) thick at their base diminishing to under 0.9m (3ft) at 22m (72ft), above this the lantern makes a total height of 30.2m (99ft). The tower is non-residential, but has a floor over the 2.4m (8ft) high ground-floor oil-store which is ceiled by a shallow vault of slabs. A similar vault carries the next stage 9.1m (29ft 8ins) above the ground at the level of the blocked low-light; above this the interior is open and contains a cantilevered stair. In the east wall of this second floor can be traced the outline of a 1.2m (4ft) wide blocked window with a shouldered head, and this feature is clearly expressed externally by recessed blocking and a projecting or hooded lintel. Nothing is known of the history of this opening which was clearly intended to display a sector light, perhaps intended to assist landing. The present lantern of 1856 is a 4.27m (14ft) wide chamfered octagon, its glazing is rhomboidal with two horizontal glazing bars and inclined uprights. The light itself remained fixed, rather than revolving. The lower iron walling is 1.5m (5ft) high and the glazed area 3m (10ft) high, its cost was £2,950 16s 7d. The present revolving apparatus was installed in 1873 and this entailed the reconstruction of the lantern floor and the provision of a weight tube down to the second floor. This gives a group of five flashes. The vapourizing oil lamp was replaced by electricity shortly before 1973. The installation of the generators resulted in the fog signal changing to the electrical emitters installed in a new building to the west. The original keepers' houses have a connecting corridor to the lighthouse tower through its east wall. They have now been converted to other uses and new dwellings have been erected to the south-east. The station also retains a circular, nineteenth-century vaulted oil store or magazine.

Event and Historical Information:
An application to place a light here was first made in 1816 by Lt. Thomas Evans RN, but several other applications made in 1820 finally resulted in the building of the tower by the Corporation of Trinity House. The light was first exhibited on 24 December 1821. Joseph Nelson is recorded as both engineer and builder. The original illumination was by reflectors, but these were changed for a dioptric (refracting) apparatus in 1838; the appearance of the original lantern is not known. Bardsey Lighthouse is now an automatic light operated from the Holyhead Control Centre. The keepers' houses are leased out to the Bardsey Island Trust.

Sources include:
Hague, D, 1994, Lighthouses of Wales: Their Architecture and Archaeology, pg60-4
Royal Commission on Lights and Buoys, 1861.

RCAHMW, Janaury 2009.

2. Bardsey Island lighthouse is a sea light located on the southern tip of the island, off the Llyn peninsula, marking the division between Cardigan and Caernarfon Bays. It was built by Trinity House in 1821. The tower is 30.2m (99 ft) high, built of ashlar limestone unplastered inside and out, but painted externally. It is unusual amongst Trinity House towers in having a square plan and is the tallest square tower of any lighthouse site in the British Isles. It is also one of the few to retain its original gallery railings. The tower plinth is 4m (13 ft) high. At ground level the structure is 7.6m (25 ft) square reducing to 6.1m (20 ft) at the top of the plinth and to 4.6m (15 ft) at the summit of the tower below the crowning cornice which is 5.5m (18 ft) square. The present lantern (of 1856) is a 4.27m (14 ft) wide chamfered octagon. Its glazing is rhomboidal with two horizontal glazing bars and inclined uprights; the light remained fixed rather than revolving. The original keepers' houses have a connecting corridor to the lighthouse tower through its east wall.
The lighthouse is now an automatic operated from the Holyhead Control Centre, the keepers' houses leased to the Bardsey Island Trust.
Source:
Exrtract from D.B.Hague, Lighthouses of Wales, ed. S.R.Hughes (RCAHMW 1994), p.60-4).

RCAHMW, 4 August 2017