In this file photo taken on March 25, 2017, an EU flag and a Union Jack flag held by a demonstrator (not in frame) is seen with the Big Ben in the background, in central London, Britain. (DANIEL LEAL-OLIVAS / AFP)

Years of wrangling over Britain’s future trade relationship with the EU are set to enter what could be their final week, with Boris Johnson’s government saying there remains a significant gap on the issue of how much fish European trawlers should be allowed to catch in British waters.

Michel Barnier, the EU’s lead negotiator, has proposed that the EU’s share of the catch be cut to 15 percent to 18 percent, an offer that Downing Street dismissed in a statement as “risible.”

Michel Barnier, the EU’s lead negotiator, has proposed that the EU’s share of the catch be cut to 15 percent to 18 percent, an offer that Downing Street dismissed in a statement as “risible”

“The EU side know full well that we would never accept this,” according to a government official. “No agreement is arguably underpriced.”

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Access to Britain’s fishing waters has been one of three key hurdles to an agreement -- the others being a level competitive playing field, and how any agreement will be enforced. But the absence in Downing Street’s statement of any mention of these two other issues could spur expectations that a deal is within reach.

A report in The Times newspaper suggested that the European Commission President Ursula von der Leyen is putting pressure on Barnier by sending one of her most trusted officials to the talks. Citing two unidentified UK government officials, the report said the parties should agree to the basis of a trade relationship by next weekend.

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Failure to reach a deal would result in extra costs for millions of consumers and businesses from Dec. 31.