Britain has issued a hardline stance in a fishing dispute with France, stating that the European nation has 48 hours to back down or face an escalating trade dispute.

The initial dispute culminated in French authorities detaining the Cornelis Gert Jan, a British scallop dredger near Le Havre. Paris threatened sanctions that would start Nov. 2 and could complicate trade between the two countries.

British Foreign Secretary Liz Truss told Sky News that the issue “needs to be resolved in the next 48 hours.”

The British trawler kept by French authorities docks at the port in Le Havre, western France, Thursday, Oct. 28, 2021. French authorities fined two British fishing vessels and kept one in port overnight Thursday Oct.28, 2021 amid a worsening dispute over fishing licenses that has stoked tensions following the U.K.’s departure from the European Union. (AP Photo/Michel Euler)

“The French have made completely unreasonable threats, including to the Channel Islands and to our fishing industry, and they need to withdraw those threats or else we will use the mechanisms of our trade agreement with the EU to take action,” Truss said. “If somebody behaves unfairly in a trade deal, you’re entitled to take action against them and seek some compensatory measures.”

“And that is what we will do if the French don’t back down.”

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French authorities encountered two British fishing vessels last Wednesday, issuing a verbal warning to one and detaining the Cornelis when the crew failed to prove it was allowed to fish in French territorial waters.

France has held a hard line after the U.K. did not issue French vessels the expected number of licenses to operate inside British waters.

A British fisherman who refused to be identified stands in the British trawler kept by French authorities docks at the port in Le Havre, western France, Thursday, Oct. 28, 2021. French authorities fined two British fishing vessels and kept one in port overnight Thursday Oct.28, 2021 amid a worsening dispute over fishing licenses that has stoked tensions following the U.K.’s departure from the European Union. (AP Photo/Michel Euler)

Environment minister George Eustice claimed the boat was on a list provided by the Marine Management Organization (MMO) to the European Union. He insisted the E.U. granted a license to the vessel, but it was unclear why the license appeared to have been withdrawn.

“We believe these are disappointing and disproportionate, and not what we’d expect from a close ally and partner,? U.K. Environment Secretary George Eustice told lawmakers, as Britain accused France of raising tensions.

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MacDuff Shellfish of Scotland, which owns the vessel, said the crew was in “good spirits.” The captain reported that French authorities questioned him, and the company provided him legal representation, according to the BBC.

The captain was back on his vessel, but the Cornelis was “not at liberty to leave” while the investigation continued.

The British trawler kept by French authorities docks at the port in Le Havre, western France, Thursday, Oct. 28, 2021. French authorities fined two British fishing vessels and kept one in port overnight Thursday Oct.28, 2021 amid a worsening dispute over fishing licenses that has stoked tensions following the U.K.’s departure from the European Union. (AP Photo/Michel Euler)

The French government suggested that it might increase customs checks for goods, stop British fishing boats from unloading in French ports and restrict energy supply to the Channel Islands, which lay between France and Britain.

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Britain claimed that it issued fishing licenses to vessels with demonstrated records of operation in British waters prior to Brexit, which occurred Jan. 31, 2020.

The Associated Press contributed to this report.