HM Fort Roughs was one of several
World War II installations that were designed by
Guy Maunsell and known collectively as
His Majesty's Forts or as
Maunsell Sea Forts; its purpose was to guard the port of
Harwich,
Essex, and more broadly, the Thames estuary. This 4500 ton artificial naval installation is similar in some respects to "fixed" offshore oil platforms. It is situated on Rough Sands, a
sandbar located approximately from the coast of
Suffolk and from the coast of
Essex. Today it is the location of the self-proclaimed and unrecognised state, the
Principality of Sealand.