Boris Johnson claimed the Brexit talks were in a “serious situation” after a call with Ursula von der Leyen, even as the EU’s chief negotiator raised hopes of a weekend Brexit agreement by persuading the European parliament to delay its deal deadline to Sunday. In a statement released after a short stock-take telephone call on Thursday evening with the European commission president, the prime minister repeated his suggestion that it was “very likely” that an agreement would not be reached, with fisheries the standout issue. Downing Street said Johnson had told Von der Leyen that the UK “could not accept a situation where it was the only sovereign country in the world not to be able to control access to its own waters for an extended period and to be faced with fisheries quotas which hugely disadvantaged its own industry”. The statement claimed Johnson had insisted that the EU’s negotiating stance on access to British waters was “simply not reasonable, and if there was to be an agreement it needed to shift significantly”. “The prime minister repeated that little time was left,” the statement added. “He said that if no agreement could be reached, the UK and the EU would part as friends, with the UK trading with the EU on Australian-style terms.” The UK’s chief negotiator, David Frost, tweeted on Thursday night: “The situation in our talks with the EU is very serious tonight. Progress seems blocked and time is running out.” While EU access to British waters remains a difficult issue, during a briefing with leaders of the European parliament’s political groups earlier on Thursday, Michel Barnier, who has led the EU negotiation for four years, said he believed a deal could still be rapidly wrapped up. Barnier cautioned against setting an early cutoff that could not be met after a suggestion from Manfred Weber, the German leader of the centre-right European People’s party, who said a consent vote could only be staged at the end of the month if a trade and security deal was secured on Friday. Barnier described it as “difficult but possible” for a deal to be struck within the 24-hour deadline if remaining difficulties over EU access to British fishing waters could be overcome, but suggested it could take a “few days”. “There is still a lot of work to do on fisheries,” Barnier told the leaders. In a subsequent statement, the parliament’s leaders – apart from the Greens, who withheld their backing due to lack of time for scrutiny – said they would hold a vote on 28 December if there was agreement by midnight Brussels time on Sunday. In her own statement after the call, Von der Leyen also offered a more positive assessment of the state of the negotiations. She said: “We welcomed substantial progress on many issues. However, big differences remain to be bridged, in particular on fisheries. Bridging them will be very challenging. Negotiations will continue tomorrow.” During his briefing of senior MEPs, Barnier had said he believed there was still a pathway to a deal within days and promised that parliament would swiftly receive the legal text of a deal once Johnson and Von der Leyen had signed it off. Dacian Cioloş, the former prime minister of Romania, had argued that the gravity of a no-deal outcome demanded flexibility from the parliament, asking: “Can we block an agreement for the sake of a few days?” Deadlines have come and gone throughout the Brexit talks. In an appearance in front of the Commons Brexit select committee, the cabinet minister, Michael Gove, said he believed failure to find an agreement remained the most likely outcome. “I think regrettably the chances are more likely that we won’t secure an agreement, so at the moment less than 50%,” he said. The EU capitals could still provisionally apply a deal successfully negotiated before 31 December if the European parliament does not vote on the deal. MEPs would then vote in January after holding debates, but the European commission is opposed to going ahead without parliament having its say in the remaining two weeks of this year. Barnier told MEPs that given all sides were against the so-called “provisional” application of a deal, the failure of the parliament to hold a consent vote in the event of a deal being brokered would leave a few weeks after 31 December without any arrangements in place, raising the stakes for a deal within the next 72 hours. He said fisheries was the most difficult issue, with Frost insisting that – because the UK had moved on the issue of future standards – the onus was on the EU to compromise on fishing demands. Barnier argued in response that in accepting that the UK would have the unilateral ability to close its waters after a transition period, the EU had already moved. He added that the UK would repatriate a significant amount of the catch currently taken by European fishing vessels in British seas, although not the 60% being sought. There is also a continuing debate over EU access to the zone six to 12 nautical miles from the UK’s coastline, with No 10 insisting it should be for exclusive use by British vessels. Barnier tweeted: “Good progress, but last stumbling blocks remain. We will only sign a deal protecting EU interests & principles.” Agreement has been struck on a range of other issues, including the right, where there is a breach of the treaty, for one side to trigger cross-suspension – meaning if a problem arises in one sector, action can be taken in another. Barnier said the UK was seeking to leave financial services out of the mechanism but Brussels was pushing for its inclusion. He told MEPs that the UK had shifted on the previous big sticking point of the “evolution clause”, under which there would be a route to apply unilateral tariffs should there be evidence that regulatory divergence was leading to one side losing out. Discussions on state aid were continuing, he said, with many of the issues resolved, but the EU wanted European businesses to go to the UK courts should there be evidence that shared principles on subsidy control had not been followed by a new domestic enforcement body.