In 1967, former British Army major Paddy Roy Bates occupied HM Fort Roughs, an abandoned World War II Maunsell Sea Fort off the coast of Suffolk, declaring it the sovereign Duchy of Sealand. In 1978, Alexander Achenbach, a German lawyer who claimed to be Sealand's Prime Minister, hired a group of German and Dutch mercenaries to launch a coup while Roy Bates was away in Austria. Flying in via helicopter, Achenbach's men stormed the platform and took Bates' son, Michael, hostage for several days before releasing him to the Netherlands.
Refusing to surrender his micronation, Roy Bates launched a daring counter-attack alongside armed friends using a jet-powered helicopter. Armed with weapons, they retook the platform and held Achenbach and his associates as prisoners of war. While the foreign mercenaries were sent home, Achenbach held a Sealand passport and was charged with high treason against the micronation, fined 75,000 German marks.
Germany requested assistance from the UK, but Britain claimed no jurisdiction over the offshore platform. Consequently, West Germany was forced to dispatch a diplomat from its London embassy directly to Sealand to negotiate Achenbach's release. Bates argued that this official diplomatic visit constituted de facto recognition of Sealand's sovereignty before eventually releasing the captive lawyer.