The treasures were illegally salvaged by four divers, who lived in Norfolk and Suffolk, from a ship called the Pollux, which sank off the Italian island of Elba in 1841.

Metropolitan Police Detective Sergeant Vernon Rapley, the head of the Arts and Antiques Unit, left for Florence on Tuesday to present the artefacts to the Italian Minister for Culture.

They are then expected to be given to a museum in Pisa.

I am delighted that we were able to stop these artefacts from being sold into the open market and return them to their rightful owners - the Italian people

Detective Sergeant Vernon Rapley

According to a report earlier this year on diving website Divernet, the four recovered 311 gold coins, 2,000 silver coins, several diamonds and some gold jewellery.

Police said they also recovered chinaware, portholes and even one of the ship's toilets.

The divers had pretended the treasure came from another ship hundreds of miles away.

The objects were discovered when police visited a west London auction house in June last year and earlier this year the four were formally cautioned under the Merchant Shipping Act.

A police spokesman said the ship had been carrying many wealthy passengers when it went down in 135 metres of water and contained an impressive amount of valuables.

Mr Rapley said the investigation was a good example of British and Italian law enforcement working together.

"I am delighted that we were able to stop these artefacts from being sold into the open market and return them to their rightful owners - the Italian people," he said in a statement.