Flat Holm is a small, almost circular island, approximately 500 metres in diameter. It rises in a gentle slope from the exposed western rocky shore to more sheltered easterly cliffs, at the top of which stands the prominent lighthouse.
In the 1860s the island was fortified with a battery of guns.
On May 13, 1897, Guglielmo Marconi, assisted by George Kemp, a Cardiff Post Office engineer, transmitted the first wireless signals over water from Lavernock (near Penarth in Wales) to Flat Holm. The message sent in Morse code was ‘ARE YOU READY.’
Flat Holm has also been the site of a cholera sanatorium, but is now uninhabited and is known for its gulls and shelducks. Boats sail to the island from Barry. There has been a lighthouse on the island since the 18th century, originally built by William Crispe. Lighthouse keepers lived at the lighthouse until it was automated in 1988. An annual service is held to bless the island.
In 1975, South Glamorgan County Council leased the island for the next 99 years, and Flat Holm is now designated as a local nature reserve, as stipulated in that lease.
It is currently run by Cardiff City Council and is home to over 3,000 pairs of lesser black-backed gulls, 300 pairs of herring gulls, 2 pairs of greater black-backed gulls and varying numbers of shelduck and oystercatchers. A large number of song birds also nest and the island has a rich and varied flora and fauna. Residential groups stay at the island from March to October and day trips are also possible.
The name Holm or Holme derives from the Scandinavian for river island. The nearby Steep Holm is considered part of England (Ed’s Note: by some).
Flat Holm Battery
Flat Holm Battery is a series of gun emplacements on Flat Holm Island in the Bristol Channel. Is part of a line of defences built across the channel to protect the approaches to Bristol and Cardiff.
The island was fortified in the 1860s as part of the works suggested in the Royal Commission on the Defence of the United Kingdom of 1860. There are four emplacements, running from the northern to southern point of the island along the western coast. In total, nine 7″ RMLs were placed on the island. The barracks for the battery were near the southernmost emplacement. This arrangement was vacated in 1901.
On the outbreak of World War II the island was rearmed with four 4.5″ guns and associated searchlights to be used for air and close defence. A Radar station was also placed on the island. These works were abandoned after the war and the site has had no military use since.
Flat Holm Society
The Flat Holm Society was set up to compliment the work done by the Flat Holm Project who manage the island.