French fishing crews have blocked French ports and ferry traffic across the  Channel to disrupt the flow of goods to the UK, in the continuing dispute over post-Brexit fishing licences.

The action is the latest tension point between the neighbouring countries, which are also trading blame for not doing enough to prevent the deaths of at least 27 migrants whose boat sank on Wednesday off Calais, in the choppy waters of the world’s busiest shipping route.

French fishermen are angry at the British government for not granting more licences to fish in UK waters — and angry at their own government for not doing more to defend them.

The fishing industry is economically tiny but symbolically important for both Britain and France

Friday’s blockades are “a warning shot”, Olivier Lepretre, president of the regional fishing committee, told reporters in Calais.

“The British have access to the European market, while we do not have access to British waters. This is not normal, the British government must respect the agreement.”

Fishing crews blocked access to the port of Saint-Malo from 9am to 10am, but that blockade, now over, has passed the baton to Calais and Ouistreham, where the protest is continuing.

Meanwhile, protesters are gearing up to block access to the freight terminal of the Channel Tunnel between France and Britain. In the port of Calais, a blockade of ferries began at noon, stopping all ferries that provide links with the UK. Five fishing boats from the port of Boulogne-sur-Mer blocked access to Calais, in a short but damaging 90-minute operation.

“This is a symbolic action but if it continues we will show more teeth,” Mr Lepretre added, in quotes given to French media.

The fishermen are protesting to “respond to the derisive and humiliating attitude of the English,” said Gerard Romiti, president of the French fishing committee.

“We don’t want handouts, we just want our licences back. The UK must abide by the post-Brexit deal. Too many fishermen are still on the sidelines,” he added.

A spokesman for UK Prime Minister Boris Johnson said the UK was “disappointed by threats of protest activity”.

Before Brexit, French fishermen could fish deep inside British waters. Now they need to be granted a special licence from British authorities to fish in certain areas. Most French boats have received the special licences. Now the dispute boils down to just a few dozen French licences that have not been granted by the UK.