A failure to agree on fishing rights has the potential to scupper attempts by Britain and the European Union to agree a new trade deal, Ireland's foreign minister Simon Coveney warned on Monday.
"If there isn't an agreement on this, the whole thing could fall on the back of it and that's the worry," Coveney told Ireland's Newstalk Radio.
While fishing alone contributed just 0.03% of British economic output in 2019, it is an emotive subject; many Brexit supporters see it as a symbol of the regained sovereignty they hope leaving the EU will bring. Combined with fish and shellfish processing, the sector makes up 0.1% of UK GDP.
Britain wants 'zonal attachment' to agree a total allowable catch for the United Kingdom's waters - a step that would give it a much larger quota share than if the fish maths were worked out on the EU's proposals.
"All we're asking for ... is there to be annual negotiations based on the science and also for there to be a move towards a fairer, more scientific sharing methodology, which is called zonal attachment, which is broadly where the fish are to be found," Eustice told BBC radio.
"Under that analysis we currently only have access to about half of the fish in our own waters. That is profoundly unfair on our fishermen - we've been clear throughout that needs to change."
Running Out Of Time
Britain and the European Union cautioned each other on Monday that time was running out for a Brexit trade deal as negotiators sparred over state aid, enforcement and fishing in a bid to avoid a tumultuous exit in just a month's time.
The United Kingdom finally leaves the EU's orbit on 31 December when a transition period of informal membership ends, though both sides are rushing to hash out a deal that will govern nearly $1 trillion in trade.
Prime Minister Boris Johnson, who is grappling with Europe's worst official death toll from COVID-19, says a deal would be preferable but that Britain would flourish without a deal when it goes it alone after 48 years of membership.
"We really are now running out of time. This is the crucial week - we need to get a breakthrough," British Environment Secretary George Eustice told Sky, adding that if good progress was made this week then negotiations could be extended.
The EU delivered a similar message.
'Truth Of Brexit'
"We are running out of time here," said Ireland's Brexit supremo, Foreign Minister Simon Coveney. "The truth of Brexit is now being exposed in terms of the challenges of it."
Talks between EU chief negotiator Michel Barnier and British chief negotiator David Frost continued on Sunday. British Foreign Secretary Dominic Raab said it was a significant week for Brexit.
"David Frost had made clear that we're continuing the negotiations because we still think there is a prospect that we can get an agreement and while there is we should persevere with those," Eustice said.