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 4,500 ton artificial naval installation is similar in some respects to “fixed” offshore oil platforms. It is situated on Rough Sands, a sandbar located approximately 11 kilometres (6 nmi) from the coast of Suffolk and 13 kilometres (7 nmi) from the coast of Essex. Today it is the location and de facto capital of the self-proclaimed and unrecognised state, the Principality of Sealand.
On the afternoon of 23 June 2006, the top platform of the Roughs Tower caught fire due to an electrical fault. A Royal Air Force rescue helicopter transferred one person to Ipswich hospital, directly from the tower. The Harwich lifeboat stood by the Roughs Tower until a local fire tug extinguished the fire. All damage was repaired by November 2006.