LONDON — It’s been called the “scallop war” — a simmering rivalry that spilled out into the open again this week when French and British vessels clashed in the English Channel, French fishermen tossed what appeared to be smoke bombs at their rivals, and the British called on the Royal Navy for protection.

Video footage on French state television and on social media showed about 35 small French fishing boats menacing five larger British vessels early Tuesday morning in a stretch of international waters that separates Britain from the rest of Europe, just off the northwest coast of France.

At least one French boat slammed into the side of a Scottish vessel.

A French official said no one had been injured in the clash, but called the encounter “extremely dangerous.”

The French argue that British fishing vessels have an unfair advantage. The French government does not allow fishing for scallops to begin until October, in order to preserve the stock.