The waters for French fishermen are being stirred up by uncertainty of what will happen if Britain leaves the EU without a deal on October 31 and their boats barred from British waters.

A no-deal Brexit would likely end access for French boats to British waters and, in France, fishing industry players fear this will not just increase tensions with rivals across the Channel but between themselves.

Sophie Leroy, whose Armement Cherbourgeois company operates three fishing vessels off the northwest coast of France, says there have been almost daily checks of their boats by the British authorities.

Earlier this month, her boats were stopped for what she described as an interminable set of checks 21 miles off the English coast.

Her boats were also surrounded by 15 British fishing vessels, she said.   "And they were saying, 'We are going to do the same as what the French did to us last year'."

The "Scallop Wars" in 2018, when French and British fishing vessels clashed over access to scallops off France's Normandy coastline, was finally settled by the two sides in a deal last September.

While a Brexit deal would help put a framework in place, Britain anticipates the possibility of more clashes between rival fishing vessels if the country pulls out of the EU with no agreement in place. The government last week released a study of that scenario, codenamed "Operation Yellow hammer", after a copy of the document was leaked to the press.

One issue it addressed was the possibility that EU vessels could illegally enter British waters, leading to "clashes between vessels", "violent disputes" or even the "blockading of ports". So far this time around the two sides have not actually come to blows.             But Leroy referred to what she called a "war of nerves" online.