UK ministers said they ‘would never trust France again’ if they cut Britain’s power in response to a row over fishing permits for Jersey.
It comes as France’s Europe minister Clement Beaune accused Britain of not keeping its promises as signed under the Brexit deal.
He told Europe 1 radio: “Enough already, we have an agreement negotiated by France, by Michel Barnier, and it should be applied 100 per cent. It isn’t being.
“In the next few days, and I talked to my European counterparts on this subject yesterday, we will take measures at the European level or nationally, to apply pressure on the United Kingdom.”
He added: “We defend our interests. We do it nicely, and diplomatically, but when that doesn’t work, we take measures.
“For example, we can imagine, since we’re talking about energy… the United Kingdom depends on our energy supplies.
“It thinks that it can live all alone, and bash Europe.”
But a Cabinet minister told Mail Online that if France cut the UK off its power supplies, Britain would “just never use them again”.
“Why would you ever go back to a provider who did that? Trust would be gone. They would be damaging themselves in the long-term,” the minister added.
Last month, France has threatened “retaliatory action” after it accused the UK for “taking French fishing hostage”.
Sea minister Annick Girardin lashed out at the decision to refuse three-quarters of licence applications for small boats in British waters – with only 12 out of 47 French boats under 12 metres granted permission.
She said it is a “new refusal of the British to apply the conditions of the Brexit accord”, adding: “French fishing must not be taken hostage by the British for political ends.”
But UK’s Department for Environment, Food and Rural Affairs told Sky News that the decision was “reasonable” and follows the Brexit agreement.
Clement Beaune said the country will “not hesitate to take retaliatory action”, sparking fears of another fishing war in the Channel.
French MP Jean-Pierre Pont, who represents coastal town Boulogne-sur-Mer, warned UK’s actions could result in French fishermen blocking ports and lorries wanting to enter the tunnel.
He said: “Be warned. Since the British are refusing to honour what they signed, as with other Anglo-Saxons in another area, the French fishermen of Boulogne-sur-Mer may be obliged, after nine months of useless patience, to envisage ways to retaliate against the UK.
“For example, by blocking ports or the entry of lorries towards the UK through the tunnel.”
Earlier this year, French fishermen protests prompted Royal Navy vessels, and the situation was described as being “pretty close to an act of war”.
The head of the joint Normandy-Brittany sea authority declared they were “ready for war” as tensions threatened to spill over in the Channel.
Related: French official says “we’re ready for war” as police vessels arrive in Jersey
French fishing blockade ‘like an invasion’, rages Jersey fisherman