St Thomas à Becket Chapel was constructed in 1180 and dedicated to St Thomas Becket. It commanded fine views of the Haven estuary, situated on the north bank in open space. Along with two other chapels, now disappeared, at Herbrandston and St Anne's Head, it functioned not only as a Catholic place of worship, but also as a Beacon Chapel, or lighthouse to sailors. The chapel enjoyed a dependent relationship with the nearby Pill Priory. By the 17th century the structure was in ruins, when it was occupied by Parliamentarian forces in 1644. It later acquired a function as storage for the battery located on the Rath.
In the twentieth century, it had become used as a pigsty and stable. In 1930, £1,000 was raised, and the building was reconstructed, work completed in 1938. It was re-consecrated as an Anglican chapel of ease. It is built of rubble stone with a graded slate roof, small nave and chancel, both with pointed barrel vaults. The interior is simple with plastered vaults, small niches each side in chancel and a curved rood beam with rood. The nave south facing windows have stained glass of 1935 and 1939 to Sir Hugh Thomas of Castle Hall. In 2012 it was privately sold, in spite of local opposition.
References:Towering 52 meters above the sea, Bengtskär lighthouse is the tallest one in Scandinavia. The building started in in 1905 after the shipwreck of S/S Helsingfors and was completed in 1906. The lighthouse was designed by architect Florentin Granholm. On December a special petrol lantern, designed and built in Paris, was brought to Bengtskär and installed atop the tower.
German fleet bombarded Bengstkär in the First World War in 1914. Since the Gulf of Finland was heavily mined, it was not until 1919 that the surrounding seas were declared safe for shipping, that the light was lit again.
After the war the military value of Bengtskär increased as part of the defence system of independent Finland. In Second World War (1941) Soviet Union made a suprise attack to island. After a bloody battle, the small Finnish garrison emerged victorious. Intermittent repairs to the facility continued during the post-war period.