Brussels has spelt out plans to lock in access for its fishermen to Britain's waters, proposing a draft treaty that would guarantee fishing rights even if annual quota negotiations with the UK collapsed.
EU chief Brexit negotiator Michel Barnier included the plans in a 441-page legal draft of the future EU-UK relationship that he circulated to member governments this week.
Mr Barnier said on Friday that the text, which sets out Brussels' vision of how the two sides' partnership should work, showed that an "ambitious and comprehensive future relationship is possible" with Britain.
But the text also underlined how far apart respective British and EU negotiating positions are at a time when face-to-face talks have been put on hold because of the spread of coronavirus.
Mr Barnier and his UK counterpart David Frost were forced to cancel a planned negotiating round in London next week as the prospect of more than 100 EU officials crossing the Channel for three days of intensive talks became unrealistic given the public health emergency. The two sides are exploring alternative options such as videoconferencing.
Fish is one of the most sensitive issues in the negotiations. Although the fishing industry represents a relatively small part of the UK economy, it is closely linked to Britain's demands to reclaim sovereignty after Brexit.
EU leaders have warned in the past that the UK's financial services sector could lose access to European markets unless Britain agrees to open its waters to EU fishing boats.
In its draft treaty, Brussels directly counters Britain's insistence that access to fisheries will depend entirely on annual negotiation.
This is a sovereign UK resource and we will decide access to it on our terms
Michael Gove, cabinet office minister
The EU draft enshrines the principle that "each party shall authorise the fishing vessels of the other party to engage in fishing activities in its waters."
The two sides would negotiate each year on the "fishing opportunities" they would have in each other's territory, but even if those talks broke down contingency arrangements would kick in guaranteeing that fishing could still take place.
Brussels wants the treaty to specify both sides' percentage share of fishing rights for 97 different stocks that straddle EU and UK waters. Setting those percentages - which Brussels has deliberately left out of the draft - promises to be one of the most difficult challenges in the future-relationship talks.
If annual negotiations break down, then these distribution percentages would still apply. In such a scenario the actual amount of fish each side could take from each other's waters would be set according to international scientific advice.
The approach would provide the certainty to EU fishermen that Mr Barnier has insisted must be part of any future relationship agreement. The chief negotiator said earlier this month that the bloc would never sellout the interests of the sector.
But Michael Gove, the UK cabinet office minister, vowed this week that Britain would not allow its sovereignty to be undermined in the talks on fish.
"Michel Barnier is a tough negotiator but it is the case that this is a sovereign UK resource and we will decide access to it on our terms," he told MPs. Britain has insisted that access must hinge on annual talks.
The EU draft text, which was adapted from the negotiating mandate that EU governments gave to the European Commission, also reinforces other fundamental disagreements with the UK. It reconfirms that Brussels wants to keep Britain tightly aligned to its rules on state aid, with a right for the EU to take "appropriate interim measures" if it believes the UK is flouting the requirements.
The draft treaty also contains a legal lock to ensure the UK cannot scale back social rights and environmental protection in the years to come. It says that, if both sides independently choose to toughen their rules, then neither party should subsequently "weaken or reduce" its standards "below a level of protection which is at least equivalent to that of the other Party's increased level".
It also places the entire future relationship under a single governance structure, based around a "partnership council" and specialised committees. Britain has rejected such a model, saying it is seeking a number of separate international agreements with the EU covering issues such as trade, internal security and aviation.
Britain this week vowed to come forward with its own legal text on the future relations. UK chief negotiator David Frost said on Twitter on Friday that the UK would "share a draft FTA and other texts shortly".