The salvage of a sunken warship with a hold full of gold coins can go ahead under an agreement struck with the Ministry of Defence.

HMS Sussex went down in a storm off Gibraltar in the Mediterranean Sea in 1694 and was thought to be carrying nine tonnes of gold coins belonging to the Treasury.

Today, the treasure would be worth up to �2.8bn.

Under international law the warship and its cargo is considered to be the property of its home country.

Profits

But Florida-based firm Odyssey Marine Exploration found the ship in 1998 and now the MoD has agreed to share the booty if it salvages it.

The salvage project is expected to begin next year and Odyssey will spend three to six months exploring the wreck, which is a half-mile deep.

The company will cover the initial costs, which could be more than $5m (�3m).

It requires special technology and robots to get the treasure as the ship is too deep for divers to reach

MoD spokeswoman

The deal allows Odyssey to claim 80% of the first $45m (�30m) made from selling the coins.

Any proceeds between $45m and $500m will be split 50-50 between Britain and the company.

Anything more than that and will be split 60-40 between Britain and Odyssey.

An MoD team will be present in Odyssey's recovery ship to advise on the archaeological and cultural value of any artefacts, such as cannon, which might be found.

French war

Experts in marine salvage and history say the public-private agreement could be a new model for locating and salvaging shipwrecks.

But an MoD spokeswoman said that any decision to search other British warship wrecks in oceans around the world would be judged on a case by case basis.

She said: "This deal is certainly a first. It is an unusual case as it requires special technology and robots to get the treasure as the ship is too deep for divers to reach."

When the Sussex sank she was loaded with gold and silver that was headed to Spain to be handed over to the Duke of Savoy to fund his war against King Louis XIV during the war with France.