The Maunsell Forts are armed towers built in the Thames and Mersey estuaries during the Second World War to help defend the United Kingdom. They were operated as army and navy forts, and named after their designer, Guy Maunsell. The forts were decommissioned in the late 1950s and later used for other activities including pirate radio broadcasting. One of the forts is managed by the unrecognised Principality of Sealand; boats visit the remaining forts occasionally.

“How the forts evolved and their history is worth tracing and is explained in the following pages.”

The booklet “The Maunsell Sea Forts: A Potted History of the WW2 Thames Estuary Forts (Revised Edition)” is made and published by Frank R Turner in 1996. Donated to the library by Adrian and Liz Arratoon from London, UK ❤️

Photos by Anna Iltnere / Sea Library