France – and its fishing industry – say many more licenses should have been allocated and that patience is wearing thin. Britain says it is respecting the post-Brexit arrangements.

"This is our demonstration of the quality and ability of professional fishermen to mobilize in response to the UK's provocative, contemptuous and humiliating attitude towards them," said Gerard Romiti, president of the National Maritime Fisheries Committee.

French fishing workers have previously taken matters into their own hands. In April, they blocked trucks carrying fish from British waters to processing centers in France.

In May, the British navy dispatched two patrol boats when French boats blockaded the Saint Helier harbor in Jersey.