Emmanuel Macron this week threatened to bar British vessels from French ports in response to a perceived slight from the Government. Earlier this week, 55 trawlers failed to secure the licenses they needed to fish in Jersey waters as guaranteed by the Brexit deal. The President's conduct, which some analysts believe he is using to drum up support from coastal communities ahead of the 2022 elections, has not gone unanswered.

       Ministers have warned the country will retaliate following "belligerent" threats made by Mr Macron.

       A Government spokesman branded his conduct "disappointing and disproportionate", adding his retaliation was not compatible with the Withdrawal Agreement.

       They also pledged an "appropriate and calibrated response" if French officials carried through with these threats, which also include enhanced security checks, electricity tariffs and cutting electricity to Jersey.

       Analysts have already laid out several potential paths the UK could take in cross-channel negotiations.

       READ MORE: Fishing row would be resolved quickly if France was out of EU - expert

       The first retaliatory measure, which the Government has already taken, is to launch ambassador negotiations with France.

       The Government summoned Catherine Colonna, the French ambassador to the UK, yesterday.

       Ms Colonna will either meet with a junior Foreign Office official or receive a reprimand from the Foreign Secretary.

       The Prime Minister and Mr Macron have an upcoming opportunity for discussion.

       While their governments tend to communicate through official channels, an impromptu chat could go a long way.

       Mr Macron and Mr Johnson will attend the G20 summit in Rome this weekend, where they have an opportunity for a "brush by" meeting.

       One unlikely method British authorities could use is conceding to French demands.

       In practice, this would mean approving the outlying licenses, but the Government has already explained why it cannot do this.

       Earlier this week, Environment Minister George Eustice said the vessels could not prove they had fished in Jersey's waters.