A tiny republic off the Essex coast is denying allegations of drug-running, gun trafficking, money laundering and internet fraud.

Sealand, the former Second World War Royal Navy fort, declared independence under its owners Roy and Joan Bates in 1966. It is eight miles off the coast of Harwich.

But while Prince and Princess Bates, as they are known, holiday in the Costa del Sol, their tiny principality is being investigated by the Spanish Civil Guard.

The probe follows allegations the base is being used by an international crime ring. There is no suggestion that the Bates' family is implicated.

Reports in a national newspaper reveal the Spanish Civil Guard is investigating a big crime syndicate involving a Spanish drug baron and the Russian mafia.

Sources in Spain believe Sealand is allegedly being used in connected with drug smuggling, arms trafficking and money laundering, as well as the sale of false documents.

Measuring 140m by 40m the Sealand platform, the world's smallest country, has a Spanish internet site which claims to be "the official web site of the principality of Sealand" and describes a sovereign nation with a population of 160,000, which is rather different from the handful of people on board at any one time.

Prince Bates, a former Army colonel, and his family have not been connected in any way with the police investigation.

Speaking to a national newspaper, he said he believed one of Sealand's passports must have been picked up by someone who made forgeries of the documents.

He said: "We have issued passports - several hundred. But we have never given passports for illegal entry."

The couple's son, Michael Bates, said he was aware of the Spanish connection and had contacted the Spanish website to find out the unauthorised link.

The Bates family was today unavailable for comment.

Sealand's web address is www.principality-sealand.net But this is not the first time the state of Sealand has come under threat. In 1978 German and Dutch businessmen captured the island and kidnapped Michael.

But within a week Prince Roy, now 78, had launched a successful counter attack and retaken the island.

Gernot Putz, a 34-year-old German lawyer with a Sealand passport, was held for seven days on a charge of treason. He was released after the week with a pardon. Spain checks Sealand

Converted for the new archive on 19 November 2001. Some images and formatting may have been lost in the conversion.