Paris - France and Britain are at loggerheads over fishing rights in the Channel, with a row over the politically sensitive industry causing a major diplomatic flare up.

AFP explains the origins of the spat:

- What has caused the dispute? -

In a word, Brexit.

Britain's departure from the European Union, which came into force on January 1, ripped up agreements in place to manage fish stocks in waters around the UK and the Channel Islands.

Until Brexit, EU members including Britain had treaties and a joint fisheries policy that allocated quotas of different stocks to each nation's fishing fleet.

As part of these agreements, hundreds of EU vessels, mostly French ones, were allowed access to Britain's fish-rich territorial waters between six and 12 miles from the coast.

- So what changed? -

Fishing was one of the most difficult issues to solve in the tense Brexit negotiations, with British Prime Minister Boris Johnson promising to regain "full control" of British waters.

In the end, the two sides agreed a compromise last December that will see EU boats gradually relinquish 25 percent of their current quotas over a five-and-a-half year transition period.

After this, there will be annual negotiations on the amount of fish EU vessels can take from British waters.

Under the agreement, EU fishermen wishing to access British seas had to apply for new licences.

The licences were for more distant waters considered Britain's exclusive economic zone (12-200 nautical miles from the coast), and its closer territorial waters (6-12 nautical miles from the coast).

Fishermen needed to prove a track record of working there between 2012-2016.

- And the Channel Islands? -

They are a separate, but significant part of the picture.

Jersey is the largest of the Channel Islands, which are self-governing.

They are not part of the United Kingdom but recognise Queen Elizabeth as their head of state and depend on Britain for defence and foreign relations.

Brexit also meant the end of the Granville Bay fishing treaty between France and Jersey, which had set rules and quotas for fishing in the waters around the island.

Under the new rules, French fishermen were required to apply for new licences, which would be granted if they could prove they had worked previously in Jersey waters.

- Is the row about the licencing process? -

Yes.

Britain has accepted nearly all requests -- around 1,700 -- from EU boats to access its exclusive economic zone.

The tension is over licences for the territorial waters.

London has issued 100 licences to French boats for these waters close to its shore, while 75 requests are still pending, according to French figures from early October.

For Jersey, 111 permanent licences and 31 provisional licences have been issued, while 75 boats have been rejected, French figures show.

Rejected French fishermen say they are being unfairly restricted due to red tape and bureaucracy.

They say small boats lack the GPS equipment required to prove they previously worked there, while others complain that they are having difficulty obtaining licences for new vessels that replaced older models.

- Have there been protests? -

Yes. French fishermen sailed to the main port on Jersey in June to demonstrate, prompting Britain to send two naval patrol boats to the area.

On Wednesday, the French government announced that it would step up customs and sanitary controls on trade with Britain and ban British seafood from French ports.

The measures are set to come into effect next Tuesday.

France has also raised the possibility of reducing electricity exports to Jersey, or blocking negotiations between London and the EU on sensitive topics such as trade in financial services.

In private, some French officials point out that Britain is also dependent on Paris to prevent migrants and asylum seekers illegally crossing the Channel to England.

French flotilla gathers at Jersey port as fishing spat deepens (May 2021)

- What will happen now? -

French officials say that since they started pressuring Britain and Jersey publicly over the last few months more licences have been issued.

France is also trying to rally the rest of the European Union to its side.

Ten out of the other 26 members of the EU signed up to a statement condemning Britain's "incomplete and inappropriate" response on fishing.

Experts see little prospect for British-French ties to improve.

With elections due in France next April, President Emmanuel Macron is keen to keep the politically powerful and vocal fishing communities on side.

Britain's rocky relationship with the European Union