French fisherman have been accused of endangering the lives of British seafarers as a row over scallops turned violent.
In tense scenes, footage from the English Channel reveals rival vessels colliding with each other and objects being thrown.
It is alleged French fisherman threw smoke bombs, rocks and other projectiles at English and Scottish boats in the early hours of Tuesday morning, with holes reported to have been left in some vessels.
Around 40 French boats are claimed to have confronted around a dozen British vessels in the scallop-rich waters of Baie de Seine, off the Normandy coast.
UK fishermen are calling for the Royal Navy's protection amid fears their lives are being put at risk.
Jim Portus, chief executive of the South Western Fish Producers Organisation, said: "They are endangering life at sea by being unprofessional.
"The French might look like heroes to the French coastal communities but it's really awful to put other mariners in danger."
One of the British vessels, The Golden Promise, had a window smashed while another suffered fire damage after a flare was thrown during the skirmishes, Mr Portus said.
He also claimed a representative of the French scallop industry had spoken of his "regret" at the incidents and promised there would not be a repeat.
Mike Park, chief executive of the Scottish White Fish Producers Association, lashed out at "criminality and high seas piracy".
"At sea there is always the threat that the smallest incident can lead to loss of life and it's extremely fortunate that no one lost their lives or was seriously hurt," he said.
"We have emailed French colleagues and pleaded for an end to this messy affair.
"They have responded positively and we are now in the process of setting an early meeting in Paris tomorrow to begin to resolve this dispute."
UK boats are allowed to fish in the Baie de Seine waters most of the year but, under rules imposed by France, their own fisherman are only permitted to harvest scallops between 1 October and 15 May.
Tensions have been high between British and French fishermen for some 15 years over the issue.
Recently, UK and French fishing bodies have also agreed limits for British vessels, but talks ended without a deal this year.
French fishermen have accused the British of depleting stocks and want them to face the same rules, leading to the confrontation.
Normandy fishing chief Dimitri Rogoff said: "The French went to contact the British to stop them working and they clashed with each other."
He revealed "around 40" French boats had gathered overnight in protest at British "pillaging" of the scallop supply.
Mr Rogoff claimed French negotiators blocked a deal this year because they had had enough.
"For the Brits, it's an open bar, they fish when they want, where they want, and as much as they want," he said.
"We don't want to stop them from fishing, but they could at least wait until 1 October so that we can share," he said.
But, he added the situation would soon change after Brexit, when the UK becomes a "third party" and will "no longer have access to these areas".
One of the UK negotiators who has worked on past scallop deals has told Sky News he will be travelling to France in the next few days for fresh talks.
The UK government insisted the British vessels are "legally entitled to fish" in the area and they are in contact with the French government to encourage "meaningful dialogue" to prevent further violence.
"The safety of the UK fleet is our highest priority, and we will continue to monitor the presence and activities of vessels in the area," a government spokesperson said.
It is understood it is the responsibility of French patrol boats to deal with any such incidents in the country's waters.