Editing Fort Blockhouse (section)

{{Short description|Former military establishment in Gosport, Hampshire, England}}
{{Distinguish|West Blockhouse Fort}}
{{Use dmy dates|date=April 2022}}

{{Infobox military installation
| name          = Fort Blockhouse
| partof        = 
| location      = [[Gosport]], [[England]]
| coordinates   = 
| image         = Fort Blockhouse, Gosport.jpg
| caption       = Fort Blockhouse (centre) and [[Haslar Marina]] (right)
| map_type      = Hampshire
| map_size      = 
| type          = Fort, later submarine base
| code          = 
| built         = 1431, various additions until 1960s
| builder       = 
| materials     = 
| height        = 
| used          = 1431–1539 (as [[chain tower|blockhouse]])<br />1539–1956 (as battery)<br />1905–1998 (as submarine base)<br />1996–2020 (as training site)<br />2002- present (as RAMC barracks)
| demolished    = 
| condition     = Complete
| ownership     = 
| open_to_public = 
| controlledby  = 
| garrison      = 
| current_commander = 
| commanders    = 
| occupants     = 
| battles       = [[Siege of Portsmouth]] (1642)
| events        = 
}}

'''Fort Blockhouse''' is a former [[military establishment]] in [[Gosport]], [[Hampshire]], [[England]], and the final version of a complicated site. At its greatest extent in the 19th century, the structure was part of a set of fortifications which encircled much of Gosport. It is surrounded on three sides by water and provides the best view of the entrance to [[Portsmouth Harbour]]. As [[HMS Dolphin (shore establishment)|HMS ''Dolphin'']], the fort was for most of the 20th century the home of the [[Royal Navy Submarine Service]]. It is unique in that it was built over five centuries from its original construction as a [[chain tower|blockhouse]] in 1431 to the final addition of submarine base structures in the mid-1960s. 

Coastal fortification was abolished nationally in 1956; the submarines left in the 1990s and the fort has not been used in a military capacity since 2021.<ref>[http://www.gosport.info/History/Fort_Blockhouse_1/fort_blockhouse_1.html Fort Blockhouse History] {{Webarchive|url=https://web.archive.org/web/20070105194721/http://www.gosport.info/History/Fort_Blockhouse_1/fort_blockhouse_1.html |date=2007-01-05}} from www.gosport.info</ref> The [[Ministry of Defence (United Kingdom)|MoD]] plans to dispose of the site in 2025.