An American marine archeology firm has got the go-ahead to search for a long-lost British ship potentially carrying billions of dollars in gold. 

After successful negotiations between Spanish and British authorities, Florida-based Odyssey Marine Exploration won permission to resume the once-suspended search for the HMS Sussex, a British ship that sank near Gibraltar over 300 years ago.

In 1694, the Sussex led a British fleet into the Mediterranean on a mission against French King Louis XIV, with whom the British were at war. A violent storm struck the fleet, sinking the Sussex with 500 men and 80 guns aboard.

But the ship carried another cargo that still entices archeologists and treasure hunters.

Historians believe the 48-metre warship secretly carried a massive political bribe: approximately nine tonnes of gold coins to buy the loyalty of the Duke of Savoy, a potential ally in southeastern France. The coins are believed to be worth anywhere from $500 million to $4 billion US, project officials say.

The recovery is being attempted under a deal with the British government, the first such public-private arrangement for an archeological excavation of a sovereign warship.

The exploration agreement splits the profits or appraised values of the recovered coins on a sliding scale favouring Odyssey. The firm stands to reap anywhere from 40 to 80 per cent of the profits, depending on how much is recovered. The British government gets the rest.

British property in Spanish waters

Odyssey's archeologists have explored the region since 1998, identifying over 400 sites of archeological interest, including a Phoenician shipwreck dating from the third to fifth century BC.

Odyssey spokespersons say they have identified a site, at a depth of 1,000 metres, with cannons and ship remains that seem to match that of the Sussex, and that agrees with British naval records as to where the vessel went down.

"Basically, I would be very surprised if this site is not the Sussex," Greg Stemm, co-chairman of Odyssey, told the Associated Press.

Stemm said his team met Friday with officials of the Andalusia region in southern Spain to discuss terms for the search and when to resume it, but wouldn't say if a date had been set.
 
Odyssey had already begun exploration work off southern Spain but suspended it in 2005 after complaints from Spain.

International law stipulates that warships like the Sussex remain the property of the government that controlled them while in operation, regardless of where they are found. The Madrid government says it will respect the rule, regardless of whether the shipwreck is found in Spanish or international waters.

However, Spanish officials expressed concern that the excavation could disturb other shipwrecks lying in their waters.

Stemm said his company understood Spain's sensitivities over protecting its cultural heritage. "So we were delighted that the Sussex project was one of the initiatives that benefited from this increased good faith and understanding between the parties that we have seen of late," he wrote.

According to a press release from Odyssey, the project will include Andalusian archeologists, a measure to satisfy Spanish concerns.

"This participation … is intended to ensure that the project complies with all the applicable laws relating to the due protection of underwater cultural heritage," it reads.

In 2003, Odyssey located the wreck of the American steamer SS Republic and $75 million US in gold coins and artifacts off the coast of Georgia. That ship sank in 1865.

With files from Associated Press