An expert in Argentina has hit out at plans to extract millions of barrels from a giant oil field near the Falkland Islands. The venture, expected to cost £3 billion, is a partnership between British company Rockhopper Exploration and Israeli firm Navitas Petroleum.

Jose Cruz Campagnoli, a political science graduate from the University of Buenos Aires, claimed the project near the British overseas territory in the South Atlantic “is an act violating our sovereignty”. Argentina has long disputed UK sovereignty over the Falkland Islands and fought a brief but bloody war after launching an invasion of the British archipelago in 1982. The South American country, which refers to the islands as Las Malvinas, has previously condemned oil exploration in the area as illegal and sought to rally international support against it.

In a column for AM 750 in Argentina, Mr Campagnoli indicated Navitas Petroleum has an illegal licence “granted by the Kelper Government of Port Stanley”.

He said that in 2022, Argentina’s Energy Secretariat “declared illegal the activities carried out by Navitas Petroleum on the Argentine continental shelf”.

Mr Campagnoli said: “Resolution 240 of 2022 declared this company illegal for conducting activities without permission and banned it for 20 years from operating in our country.

“Now, [Javier] Milei’s government does not oppose it, does not make claims in international forums nor promotes legal actions against these companies. This is an act violating our sovereignty, once again with the complicity of the national government.”

The Sea Lion field is within the North Falkland Basin and 136 miles to the north of the Falkland Islands.

An independent assessment of the field pushed up the estimated recoverable oil from 791 million barrels to 917 million barrels, equivalent to double the annual output of the entire North Sea.

Rockhopper said it plans to extract 532 million barrels, up from a previous estimate of 312 million, with most of the remainder potentially recoverable under future plans.

Despite Labour’s ban on new oil and gas licences after coming to power, the Falkland Islands government has approved production in a move which underlines the self-governing territory’s autonomy over its natural resources.

The ban does not apply to the Falklands, as it is self-governing when it comes to everything except foreign affairs and defence, which are the responsibility of the British Government.

The Falklands have also refused to sign the Paris Agreement on climate change.

Islanders are said to have been largely supportive of the exploration plans during a consultation carried out last summer.

Rockhopper owns a 35% stake in the venture, while Navitas Petroleum holds 65%.

In its last update on the field, Rockhopper said a final decision on going ahead with the project was due this year, with first oil extraction pencilled in for late 2027.

The venture is expected to bring in billions for the Falkland Islands and create thousands of jobs for locals.