Britain and France sent navy and coastal patrol ships to waters near the Channel island of Jersey on Thursday as tensions spiralled between the two neighbours over post-Brexit fishing rights.
The posturing by the historic rivals was sparked by a protest by 50-70 French fishing boats, which gathered outside Jersey's main port on Thursday morning, raising fears of a blockade.
That prompted British Prime Minister Boris Johnson to send two royal navy gunboats to the area, with France following suit with two of its own coast patrol vessels.
"We won't be intimidated by these manoeuvres," French Europe Minister Clement Beaune told AFP.
The latest flare-up has been caused by a dispute over fishing rights and licensing following Britain's departure from the European Union.
At dawn, French trawlers could be seen massed in front of the Saint Helier port on Jersey, a self-governing territory that is dependent on Britain for defence.
Jersey lies just off France's northern coast and its rich fishing waters were previously open to French boats.
"It's incredible to have succeeded in getting everyone together," fisherman Camille Lecureuil told AFP onboard his boat from the port of Carteret on the French coast.
Ludovic Lazaro, a French fisherman from Granville, told AFP that "we're not really blocking. We're all outside the port."
But the departure of a cargo ship in Saint Helier was being held up, he said.
"The port captain in Jersey doesn't want to let the cargo ship out if everyone is around here. He wants everyone to leave," he said.
The British navy vessels HMS Severn and HMS Tamar arrived in Jersey's waters to "monitor the situation," the UK government said on Thursday, while a French military source said "the situation is very calm overall".
Johnson spoke to Jersey Chief Minister John Le Fondre on Wednesday, when the pair "stressed the urgent need for a de-escalation in tensions," according to a statement.
- Electric threat -
In the run up to Thursday's protest, French fishermen had been loudly complaining about new licensing requirements announced by Jersey authorities.
They view the paperwork as deliberately obstructing them -- the same charge made by other French boat owners who have denounced delays in the licensing process for access to UK waters elsewhere.
At the end of last month, more than a hundred French fishermen briefly blocked trucks carrying British fish to processing plants in the port of Boulogne-sur-Mer.
French Maritime Minister Annick Girardin escalated tensions on Tuesday by warning that France could cut electricity supplies to Jersey in retaliation, a threat condemned by the British government as "unacceptable."
But Beaune accused Britain of being to blame for failing to implement a Brexit deal that came into force on January 1 which should have guaranteed French fishermen the right to continue working in British waters.
"Our wish is not to have tensions, but to have a quick and full application of the deal," he told AFP. "That's the case for Jersey and that's the case for the licences we are waiting for in the Hauts de France" region.
One of the French patrol boats deployed to the area belongs to the gendarme military police force, the other is a coastal security vessel operated by the maritime ministry.
- Old rivalry -
The escalating tensions landed on the front pages of most British newspapers.
"Boris sends gunboats into Jersey," read a Daily Mail headline, while The Daily Telegraph said Johnson had sent the navy to the island to "face the French".
On social media, some pointed out that the confrontation was taking place just a day after the 200th anniversary of the death of Napoleon, whose rivalry with the UK crown was legendary.
The ITV news channel in Britain posted footage online of a man firing off a blank-firing musket from the Jersey port in the direction of the French vessels.
Don Thompson, president of the Jersey Fishermen's Association, said local sentiment on the Channel Island was firmly against the French.
"The French fishermen out there want conditions removed from their licences so that they can fish with no constraints in our waters, whilst our boats are subject to all sorts of conditions," he told the Good Morning Britain TV show.
The scenes in Jersey stirred memories of the so-called "Cod Wars" of the 1960s and 1970s between Britain and Iceland which saw London deploy navy vessels to protect British trawlers.
In October 2018, dozens of French scallop fishermen confronted a handful of British rivals off the French coast, with a few vessels ramming others amid stone-throwing and smoke-bombs.