New artefacts have been uncovered on the 18th Century Spanish galleon dubbed the “holy grail of shipwrecks” off the coast of Colombia.

The San José ship belonged to the Spanish Navy and was sunk by the British in 1708 as it was heading to Colombia’s port city Cartagena loaded with tonnes of gold and silver coins.

The shipwreck was discovered at a secret location in 2015 but the first robotic exploration only began in May 2024. It is estimated to be laden with as much as £16bn in treasure.

The researchers said the latest haul is an “unprecedented set of archaeological evidence”.

Among the new finds are an anchor, glass bottles and a bedpan, according to a statement from the Colombian Institute of Anthropology and History.

The ship, whose ownership remains contested, was carrying one of the largest amounts of valuables ever to have been lost at sea including chests of emeralds and some 200 tons of gold coins.

At the time, the vessel had been transporting its precious cargo to the Spanish king to help pay for his war against the British.

Almost 600 crew members went down with it in the Caribbean Sea.

“Results of this exploration have revealed an unprecedented set of archaeological evidence, which has greatly expanded our knowledge,” the institutions in charge of exploring the wreck said in a statement.

Alhena Caicedo, the director of the Colombian Institute of Anthropology and History, said it included “a series of new materials that we hadn’t seen before”.

“Among other things, pieces of wood or parts of the ship’s hull, at least remnants indicating that there was wood there, and traces of possible anchors,” she said.

“Other types of items found include nails, bottles, jars and some different materials like glass and ceramics.”

The Colombia President Gustavo Petro has made recovering the shipwreck a priority before his term in charge ends in 2026.

But there is an ongoing debate over who owns the treasure.

Spain claims the San José is a “ship of state” as it belonged to the Spanish navy when it was sunk and its contents are protected under a UN convention Colombia is not party to.

But indigenous Qhara Qhara Bolivians claim the riches were stolen from them.

And US-based salvage company Sea Search Armada has taken Colombia to the UN’s Permanent Court of Arbitration, seeking £7.8bn, over claims it first discovered the vessel more than 40 years ago.