A clash over EU access to British fishing waters could still sink hopes of a post-Brexit trade deal, Ursula von der Leyen has said, with agreement said to be “so close but yet … so far away”. In an address to the European parliament, the European commission president said the issue of domestic subsidies, so long a thorn in the side of the negotiators, had been resolved. She reported that legal assurances that environmental, social and labour standards would not be undercut had also been secured, with fruitful continuing discussions on “future-proofing” against unfair competition offering a clear path to an agreement. But Von der Leyen told MEPs that remaining disagreements on the future arrangements for European fishing fleets in UK waters could yet scupper the nine months of negotiations at the 11th hour. “The discussion is still very difficult,” Von der Leyen said. “We do not question the UK sovereignty on its own waters. But we ask for predictability and stability for our fishermen and our fisherwomen. “And in all honesty, it sometimes feels that we will not be able to resolve this question. But we must continue to try finding a solution. And it is the only responsible and right course of action.” The UK wants the power to shut down European boats’ access to its waters but the EU is seeking three months’ notice for its fleet, with the possibility of compensation or the ability to take retaliatory measures. The two sides have not yet found a middle way between the EU offer to repatriate 15% to 18% of the current EU catch by value in British seas to UK flagged vessels and Downing Street’s demand for around 60%. The UK is also refusing access to the zone six to 12 miles from the British coastline where French and Belgian fishing boats have worked for centuries. “We’ve made some progress but we are still very far apart in key areas,” a UK official said. The German chancellor Angela Merkel suggested that a deal could be secured by the end of the week to allow the European parliament to give their consent on 28 December. She said: “With the consent from all of us, the commission continues to negotiate in these hours, in these days, again until the weekend to see - or rather until the end of this week, let’s put it this way - to see whether there still can be an agreement. There has been progress but no breakthrough, but I think we will stick to our opinion, a deal would be better than no deal, but we are also prepared for the latter.” There is growing unrest among MEPs at any suggestion that the deal could be provisionally applied for 1 January and that the European parliament would rubber stamp it at a later date. The left group in the chamber, in which Sinn Féin sit, are among those demanding the right to scrutinise the deal before the end of the year given the potential impact of the agreement on millions of people across Europe. Meanwhile, the Guardian understands that at a two-hour meeting on Monday of EU and UK chief veterinary officers and chief officers of plant health, European commission officials raised concerns about British border preparations for 1 January. EU officials claimed that government health certificates that will be required for livestock, plants and animal products coming into the UK had been shoddily drafted. The concern for Brussels is in cases where the UK is used as a “land bridge” for goods, such as meat, or livestock that might come from Ireland to the continent. EU sources said the health certificates contained several substantial errors, raising safety issues and potentially limiting the quantity and type of goods that the commission would allow to flow through the UK. An EU diplomat said: “Given the high-profile role of food supplies in the UK Brexit debate this autumn, we were surprised about the degree of preparation.” A follow-up meeting of officials is planned for Friday. A UK government spokesperson said: “We continue to engage with the EU in order to prepare for the end of the transition period, including to ensure we secure the relevant listings where required for trade.”