EU nations say they will refuse to give the green light to a tariff-free customs deal with Britain unless European boats are allowed to fish in UK waters.
The demand comes amid fears from the EU’s remaining 27 states that Brussels accepting terms in Mrs May’s Withdrawal Agreement could end up costing them the upper hand in trade negotiations.
The Prime Minister is plotting to secure a UK-wide customs union as part of a backstop plan to stop a hard border in Ireland – a plan she turned to after the EU threatened to take control over Northern Ireland and coax it away from Great Britain, a move rejected by the DUP.
But France, Denmark, the Netherlands, Spain, Belgium and Germany are spearheading a campaign to scoop access to the UK’s waters, with eurocrats insisting “access to waters will remain a priority” for EU nations during Brexit negotiations.
To make matters worse, Brussels has enraged Brexiteers by demanding continued access to UK waters for EU vessels will be part of a future trade deal.
Brussels’ guidelines read: “In the overall context of the FTA, existing reciprocal access to fishing waters and resources should be maintained.”
Each member state will have a final say on the EU’s trade deal with Britain.
Anand Menon, from the UK in a Changing Europe think tank, told The Sun the issue “might get in the way for the withdrawal deal yet”.
He said: “At best it’s a warning about what awaits us. At worst it’s something that might get in the way during this negotiation itself.”
The issue of EU member states using UK waters and vice versa has plagued British fishermen throughout the year.
In September, a violent clash took place between UK fishermen and the French who rammed boats into British vessels to stop them fishing in a harbour off the French coast which was rich with scallops.
Rocks and smoke bombs were launched by more than 30 French vessels in a skirmish with a handful of British boats off the coast of Normandy.
The so-called “scallop wars” were over access to stocks in the Baie de Seine grounds.
National regulations let British ships fish there legally all year round, but French fishermen are banned from taking the molluscs between May 15 and October 1, to conserve stocks.