Tensions over fishing rights escalated on Thursday, when France seized a British trawler fishing in its territorial waters, saying it did not have the correct documentation.
Paris has since threatened to block ports and increase checks on boats, in a move that has prompted an angry reaction from London that said French threats to disrupt British trade by blocking its trawlers will be met with an “appropriate and calibrated” response.
In an interview with Sky News, Johnson said on Saturday he is “worried” that Paris may have broken the Brexit treaty with regards to fishing.
He then promised that he will “do whatever is necessary to protect British interests.”
Asked if he would rule out triggering dispute resolution measures in the Trade and Cooperation Agreement (TCA) next week, Johnson said, “No of course not, I don’t rule that out.”
“But what I think everybody wants to see (is) cooperation between the European allies and Emmanuel Macron and I share a common perspective which is that climate change is a disaster for humanity,” he told Sky News in the Colosseum in Rome, where he is attending a G20 meeting.
Fishing, which dogged Brexit talks for years, still remains a key issue between Britain and the European Union (EU). If not resolved, it could trigger the beginning of dispute measures in the Brexit trade deal.
French officials have warned that they will prevent British boats from landing their catches in some French ports next week unless the row is resolved by Tuesday.
Johnson and French President Emmanuel Macron are scheduled to see each other in a brief meeting in Rome on Sunday.
“We have been seeking to work with the French government to issue more fishing licenses, we stand ready to continue that work,” Johnson’s spokesman said.
Citing a French diplomatic source, Reuters said Macron “is in favor of calming things down.”
The TCA agreement was formed late last year, over licenses to fish in British waters following the country’s exit from the European Union.
Both Britain and France are currently accusing each other of breaching the agreement.
The TCA offers both the UK and a member of the EU to trigger a dispute settlement process against another signatory if they are unsatisfied. They can request arbitration, a consultation, and a tribunal ruling.