Monkton Barn in the distance. Foulness Island has a population of around 160 and is normally closed to non-residents, as it belongs to the Ministry of Defence. A School of Gunnery was established there in 1859 and since 2003 a private firm has been testing munitions under contract on the many firing ranges on the island. The island has a strange desolate and isolated feel to it, although the stillness and calm when guns are not firing, has a unique beauty even for the coastal wastelands of Essex.