France has threatened to cut off the supply of electricity to Jersey in a fight over post-Brexit fishing rights.
French leaders have accused the UK of using red tape to limit fishing, in breach of the agreement made with the EU last year.
France’s maritime minister Annick Girardin said of the potential electricity cuts: "We are ready to use these retaliation measures.
"Europe, France has the means – that’s written in the deal.
"With regards to Jersey, I would remind you, for example, of electricity transmission by underwater cable. So, we have the means. Even if I would regret getting to that point, we will if we have to."
According to Jersey Electricity, around 95% of the power for the self-governing British Crown Dependency comes through three undersea cables from France, with the rest provided by diesel generators on the island.
On Friday, 41 ships were authorised by the UK to fish in waters off Jersey but France said this authorisation had been accompanied by new demands "which were not arranged or discussed, and which we were not notified about".
The demands set out where ships could and could not go, how long fishermen can spend at sea, and what machinery they can use, they added.
In comments reported by The Guardian, French politician Bertrand Sorre said a vessel from Granville, which fishes for scallops and whelks "on average 40 days a year" in Jersey’s waters, had been told it would only have access for 11 days.
He added: "The anger is roaring and the desire to do battle is palpable."
Ms Girardin said these were "absolutely unacceptable", adding: "If we accept this for Jersey, it would imperil our access everywhere".
Government minister Nadhim Zahawi told Sky News the EU and UK had to "iron out" any post-Brexit issues.
"I think my very strong feeling on this is that we need to work constructively," he said.
"This is an issue for the (European) Commission to work with our team and all the indications from minister (David) Frost and his team is that the Commission is taking seriously some of these operational challenges that we need to fix together."
A spokesman for the UK’s Department for Environment, Food and Rural Affairs said Jersey was responsible for its own territorial waters and fishing management in them, but the UK was responsible for the international relations of the Crown Dependencies.
"We have been working closely with the EU and the government of Jersey on fisheries access provisions following the end of the transition period for licensing," the spokesman added.