“The court by 12 votes to three finds that the Republic of Chile did not undertake a legal obligation to negotiate a sovereign access for the … state of Bolivia,” judge Abdulqawi Ahmed Yusuf said at the end of a judgement that took an hour and 20 minutes to read out.

Yusuf said, however, he hoped that “with willingness on the part of both parties, meaningful negotiations can be undertaken”.

Bolivia’s leftist President Evo Morales – who is trying to win political capital at home through the issue as he seeks a fourth term in office – attended the court in person for the verdict.

A small crowd of Bolivian protesters waving flags and playing traditional pan pipes also gathered outside the Peace Palace ahead of the verdict.

The ICJ was set up after World War II to rule in disputes between UN member states. The court’s findings are binding and cannot be appealed, although it has no real power to enforce them.

Chile and Bolivia have had no diplomatic relations since 1978, when Bolivia’s last attempt to negotiate a passage to the Pacific broke down in acrimony.

Geoff Gordon, an analyst at The Hague-based Asser Institute, said there were “high stakes for Bolivia and Chile”.

The War of the Pacific pitted Bolivia and Peru on one side against Chile on the other, and saw battles fought in the Pacific Ocean, the Andes mountains and even in the Atacama Desert, the driest desert in the world.

Decades of post-independence border tensions in South America were finally ignited by a dispute over Bolivian attempts to tax a Chilean company mining saltpetre, a mineral used in fertiliser that was at the time replacing the traditional use of guano, the excrement of seabirds and bats.

Bolivia says regaining the 400km of coastline along the northern tip of Chile that it lost in the war would stimulate growth and development in South America’s poorest country.

Morales has also weaponised the dispute to boost his popularity at home, where the importance of the issue is underscored by the fact that Bolivia still has a navy despite lack of access to the sea.

Bolivia’s lawyers have argued that it has tried several times over the last century to discuss possible access to the Pacific, but to no avail.

Bolivian activists said the loss of the Chuquicamata mine, the world’s largest open-pit copper mine which is situated in the disputed area, has also badly hit the country’s indigenous peoples.

These attempts were continuously slapped down by the Chileans, La Paz’s lawyers said, leading to the breakdown in diplomatic relations.

Santiago, in turn, said the border is based on a 1904 peace treaty signed with Bolivia in the wake of the War of the Pacific and therefore must be respected.

Chilean Foreign Minister Roberto Ampuero said last week his country will not negotiate with Bolivia over the issue as “our sovereign territory is protected and will not be a part in anyone’s negotiations”.

Chile added that Bolivia currently enjoyed “full and unrestricted rights of commercial transit between its territory” and the Pacific ports.

But President Sebastian Pinera has not ruled out an “intermediate solution” in which the ICJ “invites parties to negotiate in good faith which may be with or without a predetermined result”.

Meanwhile, Chile has opened its own case against Bolivia over the Silala waterway, which flows into the Atacama Desert and which La Paz has threatened to divert.