Fort Luton was built between 1876 and 1892 south of Chatham, Kent. It has a polygonal trace. It was never armed, but took part in the war games held by the Army in the 1900s, including a trial siege in 1907. The site was last used in the 1990s as a model museum, but that has now closed.
External links
Fort Luton (http://www.palmerstonforts.org.uk/fortlog/lutn.htm)
Eight air samples were then sent to Fort Dietrick, a US military facility in Maryland, for testing and one tested positive for the deadly spores.
Phil Luton, a microbiologist at the UK's reference laboratory for anthrax at the Health Protection Agency in Porton Down, agrees that false positives are possible.
Luton says anthrax is "not unusual" to find in the environment.