The claims of Sealand, a former military platform off the coast of Sussex, to nationhood are complete nonsense, a leading international and maritime law expert says. Piratebay, the Swedish file-sharing links site, says it is in negotiations to buy the platform.

The Spanish estate agent acting for the self-proclaimed nation has also declared that Piratebay may not be allowed to buy it because it has pledged not to allow a sale that would damage the interests of or act against the UK.

Piratebay is the focus of a burgeoning political movement in Sweden. The server farm hosting the site was raided last year ,causing popular outcry in a country where file sharing is significantly more socially acceptable than in other European nations. The site provides links to material that is often downloadable without a license or permission.

Piratebay now wants to find a location where it can set itself up as a nation and avoid copyright laws, and says it has started negotiations with the family that has long claimed Sealand as a sovereign nation.

But Professor Robin Churchill, a lecturer in constitutional and international law at Dundee University, says that Sealand’s 1967 claim to sovereignty is absurd. “It is within 12 miles of the coast of Britain and in 1987 the UK extended its territorial waters to 12 miles. That means that UK law applies, including the law of copyright, which could be extended to Sealand without any legal problems whatsoever,” he said.