France will “now use the language of force” in an escalation of a row over post-Brexit fishing rights, France’s EU affairs minister has said, as French maritime police seized a British trawler found in its territorial waters without a licence. One vessel was stopped off Le Havre in the early hours of Thursday morning, then rerouted to the quay and “handed over to the judicial authority”, while a second was given a verbal warning. In a statement, the French government said the checks had been routine but admitted they were conducted “in the context of the discussion on licences with the UK and the European Commission”. The seized trawler was later identified as the Cornelis Gert Jan by a spokesperson for the South Western Fish Producers Organisation. The owners of the boat at the centre of the dispute told the Guardian that their vessel was properly registered with the UK authorities to fish in French or EU waters, but their vessel’s name was not included on the official register that was shared with the French government. Paris has been infuriated in recent months by the response of the authorities in the UK and Jersey to post-Brexit applications from French fishing vessels for permits to its waters, which are regulated by the EU-UK trade deal agreed on Christmas Eve last year. The row blew up on Wednesday when Paris said it would ban British fishing boats landing seafood in key ports from Tuesday next week unless it received further licences for French vessels, and vowed to impose onerous checks on cross-Channel trade. There was also a threat issued to the UK’s energy supply if those initial sanctions from Paris did not prompt the issuing of extra permits. Answering an urgent question in the Commons on Thursday, the UK environment secretary, George Eustice, condemned the comments as “not what we would expect from a close ally and partner” and warned of possible retaliation. Sources in Brussels confirmed there was not yet support among the other 26 member states for EU action against the UK through the dispute resolution mechanism in the trade and cooperation deal. Later on Thursday morning, France’s EU affairs minister, Clément Beaune, doubled down, however, on the threat of unilateral French action, saying the situation was “not acceptable”, and that the restricted number of permits was a “political choice” by Downing Street. “So now, we need to speak the language of force since that seems to be the only thing this British government understands,” he said. “We have been extremely patient, our fishing boats have been extremely responsible, because it’s a major loss of their activity. From November, it’s over. We’ll open dialogue if the British want dialogue – it’s up to them – but we’ll put in place retaliation measures because there is no reason we shouldn’t have access to their waters when they have access to our ports.” Speaking at the annual conference of the European Policy Centre thinktank in Brussels, Beaune also linked the row over access to British waters with the UK’s refusal to fully implement the post-Brexit arrangements for Northern Ireland. The risk is also now high that fishers from Normandy and Brittany will decide to blockade UK or Jersey ports. The Royal Navy has patrol ships “at high readiness” to help Jersey enforce fishing rights and maritime security over its waters, the UK Ministry of Defence said on Thursday. Insiders said Jersey would have to request the deployment of the armed “river class” offshore patrol vessels, although no such request had been received from the government of the crown dependency. British naval planners have shaken up their fishing defence plans over the last few months as tensions in the Channel have flared since Brexit. In May HMS Severn and HMS Tamar, both river class vessels, were deployed to Jersey to prevent a feared blockade by French fishing trawlers of the island’s main port. The UK has said 1,700 EU vessels have been licensed to fish in UK waters and that 98% of applications for fishing licences had been granted. Eustice repeated this statistic in the Commons on Thursday, saying the UK “stands by its commitments in the trade and cooperation agreement”. He said: “It is very disappointing to see the comments that came from France yesterday. We believe these are disappointing, disproportionate and not what we would expect from a close ally and partner.” The French maritime minister, Annick Girardin, accused Britain of spreading misinformation. “The figure of 98% of licences granted by the United Kingdom to Europeans is false,” she said. “Only 90.3% were. Obviously, the missing 10% are for the French … It has been nine months since French fishermen have no longer been able to work. It is a breach of their signature by the British. That’s enough.” The main differences between the two sides centre on rights within the six- to 12-mile zone from the British coast. Earlier this week, the European Commission said the UK government had approved 15 out of 47 applications for French boats to operate in those coastal waters. A further 15 applications were being considered where evidence of activity in those waters was limited, but 17 applications had been withdrawn by French applicants because of “poor evidence”. Of greater concern to the French authorities is that one-third of boats applying to fish in the waters off Jersey, a British crown dependency, have been turned down by the island’s government. Barrie Deas, from the National Federation of Fishermen’s Organisations, the body representing fishers in England, said the descent into a “tit for tat” relationship was unhelpful.