Boris Johnson will demand that the increasingly isolated French president, Emmanuel Macron, caves in to UK demands on fishing as the price for a trade and security deal at a key meeting with the European commission president on Saturday. The prime minister will speak to Ursula von der Leyen on Saturday afternoon in a video-conference call to “take stock of negotiations and discuss next steps”. Johnson said he was “pretty optimistic” that a Brexit deal could be reached. He told the Daily Telegraph that the prospects of securing a deal by the end of the year to avoid an abrupt separation were “very good if everybody just exercises some common sense and looks at the deal that is there to be done”. Johnson will feel strengthened by comments from the German chancellor, Angela Merkel, on Friday when she described the fisheries deal struck by Britain with Norway this week as a “constructive indicator”. British officials argue that Norway, a non-EU state that conducts annual negotiations with the bloc on fishing quotas, should be the model for a post-Brexit deal on shared stocks. “I don’t think that’s a bad message at all for us, I think it is rather one that shows that one can find ways to come to an agreement,” Merkel said of the agreement between London and Oslo. Von der Leyen said on Friday that the most contentious issues, including fisheries and the control of domestic subsidies, remained “completely open”. The EU now expects a deal to be struck only in late October or early November. In a statement, the UK’s chief negotiator, David Frost, suggested there had been movement on the issue of state aid. He made his strongest comments on access to British waters for European fishing fleet, an issue where the EU has been internally split in recent weeks. Frost said: “On the level playing field, including subsidy policy, we continue to seek an agreement that ensures our ability to set our own laws in the UK without constraints that go beyond those appropriate to a free trade agreement. There has been some limited progress here but the EU need to move further before an understanding can be reached. “On fisheries, the gap between us is unfortunately very large and, without further realism and flexibility from the EU, risks being impossible to bridge. These issues are fundamental to our future status as an independent country.” Macron has infuriated other EU capitals by insisting that Brussels takes a tough negotiating position on fisheries in favour of the status quo under which France is a major beneficiary. A number of EU representatives in Brussels have privately counselled that a deal with the UK should not be jeopardised over fishing rights given its small economic value, prompting the French ambassador to describe such comments as “unacceptable” in one meeting. Paris has insisted on retention of the status quo, under which fishing catches in the 1970s form the basis of catches today. The UK remains fixed on replacing the common fisheries policy with a system of “zonal attachment” that would offer a significant increase in catches for British fishing fleets. Currently, Britain’s economic zone is part of common EU waters. The UK receives a fixed share based on how much its fishermen caught during a reference period between 1973 and 1978. Under the new system proposed by the UK, the two sides would agree on what percentage of shared stocks are attached to each of their European economic zones each year. Catch quotas would be organised in line with that percentage. A failure to agree annually on catches could lead to EU fleets being locked out of British waters. The EU’s chief negotiator, Michel Barnier, who has repeatedly admitted that both sides should back down from “maximalist positions” on access to British waters, acknowledged the need for an increased haul for British fishermen. Barnier said a final deal would require “a stable, sustainable and long-term agreement on fisheries, enabling the UK to further develop its fishing opportunities, while ensuring the sustainable use of resources and protecting the activities of European fishermen and women.” On Wednesday the Guardian revealed that Britain had offered a three-year transition period for European fishing fleets to allow them to prepare for the post-Brexit changes as part of an 11th-hour deal sweetener. The catches of EU fishermen would be “phased down” between 2021 and 2024 to offer time for European coastal communities to adapt to the changes. Speaking to journalists at the end of an EU summit in Brussels, Von der Leyen said there remained “a lot of work to do”, with 100 days left before the UK exits the single market and customs union, but she added: “Where there is a will there is a way.”