EU chief negotiator Mr Barnier is in London for another round of trade talks with Downing Street counterpart Lord Frost. However, following an intense day of negotiations yesterday, officials on both sides admitted talks were still sluggish with the chances of a no deal Brexit rising.
A Whitehall official close to the negotiations told Express.co.uk the EU’s fishing demands could mean talks are set to judder to a halt.
They added: “It seems Barnier wants to put out doom and gloom style signals so this could be a dark period of talks.”
A UK Government spokesman added of Monday’s discussions: “Unfortunately, we haven’t achieved as much as we’d hoped during this intensive process.
“The EU doesn’t seem to realise the scale of change in fishing rights they face if there is no agreement.”
According to sources, Mr Barnier told his allies punishing tariffs could cripple UK exporters if Britain does not budge on access to waters.
Mr Barnier wants to use the promise of lucrative access to the EU’s market for key UK manufacturing sectors to secure greater access to the UK’s coastal waters for the bloc’s fishermen.
Mr Barnier told a private meeting: “I’m pitting one against the other. European access to British waters and British access to the single market.”
In Westminster, UK politicians continue to claim a deal with the EU is still possible.
Chancellor Rishi Sunak said: “As we heard from the prime minister at the weekend, we have made significant progress.
“Those talks are ongoing.
“It’s clear that a deal can be done but that will require both sides to continue to act in a constructive way, and we remain ready to do that and are working hard at it.”
And Environment Secretary George Eustice indicated a possible compromise on fisheries, which has been a major point of contention delaying progress on a deal.
But time is fast running out to have a deal in place by the end of the transition period on December 31, with businesses fearing the high trade tariffs they would face in the absence of an agreement.