The Environment Secretary has warned France that “two can play at that game” as a diplomatic row over fishing rights grows, suggesting British authorities could increase enforcement patrols on French ships in response to threats.

France detained a UK trawler on Thursday and made threats including imposing new border checks and cutting off the UK’s electricity supply.

The measures appear to be an act of retaliation for what France claims is an unjust attempt to limit the number of UK fishing licences issued to French vessels.

The row escalated on Thursday night as British Foreign Secretary Liz Truss summoned the French ambassador for urgent talks on the issue.

DEFRA minister George Eustice described the threats as “completely disproportionate”, “unacceptable” and a breach of European law.

He said just 2 per cent of vessels had been rejected and because they did not qualify for fishing rights under the terms of the Brexit agreement.

“What we’re talking about here is a very small proportion of vessels that the French have put forward to be licensed, but the truth is they just don’t have a track record of fishing in the areas where they needed out be in order to qualify for one,” he told Sky News.

“We think that the comments that have been made by France on this are completely disproportionate, that they’re unacceptable, and that the things they are suggesting doing – which is basically start to be difficult at the borders and close ports and so on – is a clear breach not only of the trade and co-operation agreement that we’ve got, but also of EU law.”

He said that the UK was asking France “to try and calm this down and remove these threats that are not acceptable”.

The minister said that he had already spoken to the EU commissioner about the threats, and that Ms Truss would “ask [the French ambassador] to explain and give an account of what they intend to do”.

“We don’t know what they’ll do,” he added. “They say they wouldn’t introduce these measures until Tuesday probably at the earliest, so we will see what they do, but obviously if they do bring them into place, well, two can play at that game, and we obviously reserve the ability to be able to respond in a proportionate way.”

When pressed on what action he could take, Mr Eustice told BBC news that the UK could “increase the enforcement that we do and board more [French boats] if that’s what they’re doing to our vessels, and there’s other administrative things we can do” but insisted he wasn’t “going to get in to all the things we might do”.

France has warned that it could impose sanctions on the UK from next month, including a ban on access to its ports, more stringent customs controls on lorries travelling across the Channel, and new tariffs on energy exported to Britain.

The country’s Europe minister Clement Beaune said: “We need to speak the language of force as I’m afraid it is the only thing this British Government will understand. We will show no tolerance, no indulgence.”