The French government has stepped back from a threat to impose disruptive port checks on lorries and boats after the UK threatened to take legal action in a row over post-Brexit fishing licences.

Key talks between the two sides will take place later this week aimed at resolving the disagreement, but the risk of further escalation remains.

Sky News examines what is behind the row between the UK and France and what measures London could take if the impasse rumbles on.

What is the dispute about?

Under the terms of the Brexit trade deal, which came into force on 1 January, EU access to UK waters and UK access to EU waters is now managed through a licensing system for fishing vessels.

The current row erupted after the UK authorities refused to give licences to some French fishing vessels to operate in UK waters because they believed they did not meet the requirements.

According to the French government, the UK has only issued half the fishing licences that Paris believes it is entitled to.

Environment Secretary George Eustice told Sky News last week that the UK has issued post-Brexit licences to 1,700 vessels, including 750 French fishing boats, which amounts to 98% of applicants.

But the row deepened when the Cornelis Gert Jan scallop trawler was detained by French authorities last Thursday near the port of Le Havre.

The owners of the British vessel denied French claims that it did not have the correct licence to fish in French waters and said the Cornelis was being used as a “pawn” in the wider UK-France fishing dispute.

France initially said that if the UK did not grant more licences for its fishing vessels it would, from Tuesday, block its ports, carry out security checks on British vessels, reinforce controls of lorries to and from the UK, reinforce customs and hygiene controls, and raise tariffs.

However, Paris has stepped back from introducing these measures.

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Downing Street says talks will take place with France on Wednesday about the situation, as well as other “issues important to the UK-EU relationship, including the Northern Ireland Protocol”.

What are dispute resolution measures?

It is against this backdrop that the UK has threatened to take legal action.

The prospect was raised by Prime Minister Boris Johnson last week and repeated by the Foreign Secretary Liz Truss in a Sky News interview on Monday.

The foreign secretary set a 48-hour deadline for the fishing dispute to be resolved, although it’s not clear if that deadline still stands in light of recent moves from Paris.

If legal action were to be taken, this would involve the UK triggering the dispute resolution measures contained in the Brexit trade deal, officially known as the Trade and Cooperation Agreement (TCA).

The measures are designed to be used when one side feels that the other is in breach of the TCA.

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Initially, this would mean a 30-day period of consultation between the two sides which can be extended if both parties agree.

The aim of this first step is to resolve any disagreement through dialogue.

But if a solution cannot be found, the complainant can progress things further and ask for an independent arbitration tribunal to be set up.

This would be made up of three members: one nominated by the UK, one put forward by the EU and a jointly-agreed chair.

The tribunal would then rule within 130 days of being set up, although an interim report would be issued earlier.

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One side can ask for this timeline to be sped up, which would see it cut in half.

Tribunal rulings are legally binding and if a side is found to have breached the agreement they have 30 days to set out how they will comply.

Sam Lowe, a senior research fellow at the Centre for European Reform think-tank, said of the process: “In terms of the legal mechanisms we are very much talking about a process here that could drag on for a while.”

What happens if one side does not comply?

The other party can ask for compensation or suspend certain obligations contained in the agreement in areas like trade, aviation, road transport and fisheries.

The tribunal can be asked to rule on whether the suspension is appropriate, while the suspension should be rescinded if the other side then decides to follow its ruling.

There are also specific steps that one side can take in relation to fishing.

What measures can be taken on fishing?

One side could decide to entirely suspend access to its waters and scrap the preferential tariff agreement that applies to fishery products.

Again, an arbitration tribunal could end up getting involved, with it ruling if the measure is a proportionate response.

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The UK, or indeed France, could choose to go further and apply tariffs on fisheries and non-fisheries products or even suspend elements of the TCA relating to trade and road transport.

Either side can also decide to bin the agreement on fisheries with a notice period of nine months.

What would the impact be on UK-EU relations long-term?

According to Sam Lowe: “If the UK feels the diplomatic route has been exhausted, proceeding with dispute resolution within the confines of the TCA is the proper way to go about things.

“At least in the TCA there are rules, processes to be followed; much better than spilling out into an unconstrained trade war with both the EU and UK free to do whatever they want.”

However, he warned that a simmering dispute could have a wider impact, adding: “These disputes do have political ramifications: they chip away at the good will necessary to reach a compromise on other outstanding issues such as Northern Ireland.”

Are the dispute resolution mechanisms different when it comes to Northern Ireland?

Yes.

The UK and EU are currently locked in talks over potential changes to the protocol, which is designed to avoid a hard border on the island of Ireland.

The protocol is part of the withdrawal agreement between the two sides and is separate from the TCA.

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If these talks break down or do not prove fruitful, either side has the option of activating Article 16 of the protocol.

This states that if the protocol is causing “serious economic, societal or environmental difficulties that are liable to persist”, or leading to a “diversion of trade” then either the UK or EU can introduce “appropriate safeguard measures” to tackle the problems.

Brussels at one stage proposed using Article 16 to stop COVID vaccine exports from the EU moving to Great Britain from Northern Ireland, but stepped back from this after a backlash.

Opponents of the protocol in Northern Ireland have been calling on the UK government to invoke Article 16 to stop checks and controls on goods.