Boris Johnson and Ursula von der Leyen have approved a further month of Brexit negotiations after agreeing that enough progress has been made to justify a last push to reach a deal on trade and security. The EU’s chief negotiator, Michel Barnier, will travel to London this week for talks with his British counterpart, David Frost, and the two sides will then hold follow-up talks in Brussels the week after. The fresh rounds were agreed after a phone call on Saturday afternoon between the British prime minister and European commission president. EU sources said the conversation was “not a game-changer” but not “unhelpful”, with both sides showing resolve to find “landing zones” on the most difficult areas. Before the new rounds of negotiation, Barnier will visit the German chancellor, Angela Merkel, in Berlin on Monday. Merkel had suggested on Friday that the EU would show fresh flexibility. In a joint statement following their call, Johnson and Von der Leyen said they had identified reasons for hope that common ground on the most contentious issues could be found. They called on their teams to intensify negotiations in the coming weeks. “They agreed on the importance of finding an agreement, if at all possible, as a strong basis for a strategic EU-UK relationship in future,” the statement said. “They endorsed the assessment of both chief negotiators that progress had been made in recent weeks but that significant gaps remained, notably but not only in the areas of fisheries, the level playing field and governance. They instructed their chief negotiators to work intensively in order to try to bridge those gaps.” Downing Street’s hopes of moving into a so-called “tunnel” negotiation – an intensive negotiation away from the scrutiny of the media and domestic politicians – have not been satisfied. “It instructs me and [Michel Barnier] to work intensively in order to try to bridge the gaps between us. That work begins as soon as we can next week,” Frost tweeted of the joint statement. In a sign that negotiations have moved into the political realm, with decisions required by both sides at the top ranks on their respective levels of flexibility, Von der Leyen and Johnson said they would now talk on “a regular basis on this issue”. Their last meeting was in June, when Johnson said it was time to put a “tiger in the tank” of the negotiations, insisting that a deal was possible by the end of the summer. He later moved his deadline to mid-October, when the 27 EU heads of state and government are due to hold a Brexit summit. Downing Street made no mention of a deadline this time. During the call, it is understood Johnson emphasised that he would prefer the kind of arrangement the EU agreed with Canada, and he repeated his willingness to leave the transition period without a deal. It is understood that while it is open to talks later in October, the government has stressed behind the scenes the importance of having clarity by the summit on 15 October on whether a deal is possible, given the need to prepare for a no-deal exit. Barnier told members of the European parliament on Friday that he believed the last two weeks of October would prove to be the “crunch period”, with the hope that a deal might be ready for ratification at the start of November. The two sides are stuck on the issues of access to British waters for European fishing fleets and the level playing field provisions being pushed by Brussels to ensure that neither side can undercut standards or unfairly subsidise businesses through state aid. Before last week’s talks, five new draft negotiating documents were submitted by the government, including legal texts on fisheries, the level playing field, law enforcement and judicial cooperation, civil nuclear cooperation and social security coordination. Britain had offered a three-year transition period for European fishing fleets, allowing them to prepare for the post-Brexit changes, as part of an 11th-hour deal sweetener. The catches of EU fleets would be “phased down” between 2021 and 2024 to offer time for the European industry to adapt to the changes, but the French government has so far refused to countenance the major changes to catches being proposed by London. On state aid, EU sources said the UK had offered to lay out a series of principles on controlling domestic subsidies. But the paper failed to offer appropriate “governance” proposals that would allow Brussels to hold the UK to its pledges, they added. On Friday, Frost said there had been progress on state aid but that the gap between the two sides on fisheries remained wide and that without a move by Brussels a deal would not be possible. It is understood that message was again relayed by Johnson to Von der Leyen during their conference call on Saturday.