Flat Holm island has had two military occupations. First in the 1860’s and again in 1940 during world war 2.
In the 1850’s, Queen Victoria & Prince Albert visited france where they became concerned about the strength of the French Navy. The Royal Commission of 1860, under the direction of Lord Palmerston recommended fortification of the coast. Flat Holm formed part of a strategic coastal defence system, a number of fortresses built across the Bristol Channel to protect the ports of Newport, Cardiff & Bristol.
Flat Holm was re-fortified after 1940 despite the heaviest raids on Cardiff being over. 350 men were stationed on the island and in addition to new building being built, existing buildings were adapted for use. The Cholera Hospital was turned into a NAAFI, cinema & concert hall, where films were shown fortnightly and concerts laid on monthly. The farmhouse was used as the officer’s mess.