The wreckage of the world’s most infamous passenger liner is set to be protected after an international agreement was ratified almost 20 years after first being proposed.

The transatlantic treaty between the United Kingdom and the United States gives both nations power to limit the number of expeditions to the remains of the Titanic following concerns over the removal of historic artefacts.

The ship has been under water for more than a century, lying in international waters about 350 nautical miles off the coast of Newfoundland, Canada.

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Although the wreck has previously been given a “basic level of protection” by Unesco, the cultural organisation of the United Nations, this is the first time it is covered by explicit legislation, according to the Department for Transport.

The UK signed the treaty in 2003, but it has only come into force following its ratification by US secretary of state Mike Pompeo in November last year, the department said.

Canada and France were involved in the negotiations but have still not signed the agreement.

Titanic was built in Belfast and set off on its maiden voyage from Southampton on April 10, 1912.

Five days later it struck an iceberg, broke apart and sank to the bottom of the North Atlantic.

Dozens of expeditions to the wreck have been carried out since it was discovered in 1985.

Experts claim many artefacts have been removed and the ship has suffered serious damage from mini-submarines landing on its surface.

Maritime Minister Nusrat Ghani said: “Lying two and a half miles below the ocean surface, the RMS Titanic is the subject of the most documented maritime tragedy in history.

“This momentous agreement with the United States to preserve the wreck means it will be treated with the sensitivity and respect owed to the final resting place of more than 1,500 lives.

“The UK will now work closely with other North Atlantic states to bring even more protection to the wreck of the Titanic.”

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She will mark the signing of the treaty with the US by visiting the 1851 Trust Maritime Roadshow for Girls in Belfast.

The event aims to inspire girls to study science, technology, engineering and maths, known as Stem subjects, which are vital in the maritime sector.

Judith Owens, chief executive of visitor attraction Titanic Belfast, said: “We welcome any additional protection and safeguarding of the wreck, in line with the views of our strategic partner Dr Robert Ballard, who discovered her in 1985.”