A summit of EU leaders on 19 November is now viewed in Brussels as the final deadline for a draft Brexit deal, with negotiations on Britain’s future trade and security relationship with the bloc set to go to the wire. Negotiators working in London had hoped to be able to pass on a deal to MEPs for scrutiny by 18 November to allow time for parliamentary ratification but the talks remain difficult, according to sources on both sides. Next Thursday’s video conference summit of the 27 heads of state and government, arranged to discuss the latest developments in the coronavirus pandemic, is being seen as a key moment in the Brexit saga. “If there isn’t good news by then, then you really have to say that time is up – it just isn’t possible,” said one senior EU diplomat. “The leaders will need to see that it is there.” A final arbitration session between Boris Johnson and the European commission president, Ursula von der Leyen, is also a possibility should the negotiators move closer to each other’s positions on the outstanding issues. The thorniest problems to resolve remain the level of access to UK waters provided to EU fishing fleets, how to maintain fair competition rules for business – including rules on domestic subsidies – and the mechanism in the final treaty for resolving future disputes. UK sources have complained that Brussels has as yet failed to show enough “realism” about the scale of the change to the level of fishing opportunities the EU member states’ fleet will have in Britain’s exclusive economic zone from next year. On ensuring a “level playing field” for businesses in the UK and the EU, progress is being made on how the two sides’ domestic subsidy regimes would operate but difficulties remain in establishing a mechanism whereby a baseline of environmental, labour and social standards would develop in tandem for both sides. Downing Street has insisted the UK needs to be able to diverge its rulebook, while the EU has said it will not grant a “zero tariff, zero quota” deal if British companies are not operating under rules that are at least equivalent to those set by Brussels. A UK source said: “We have a different view from the EU on what is appropriate on level playing field issues. We have been clear that we can look at common principles for our different subsidy systems and perhaps even at the ability to act if a major subsidy genuinely distorts trade. “What we can’t agree to are arrangements which would require us to operate systems of laws equivalent to the EU’s and make us pay a penalty if we moved away from them. We need policy space to decide what is in the UK’s interest in the future. That is the very essence of what Brexit is about.” Despite the difficulties, the prime minister said on Sunday that a trade and security deal was “there to be done” and that the broad outline was already “pretty clear”. Johnson spoke to Von der Leyen on Saturday. The sliding Brexit timeline will be a cause for concern in the European parliament, where MEPs had insisted they would need to have the agreement in front of them by next Monday to start the ratification process. It was hoped that the parliament would vote on the deal on 16 December. Sources in the European parliament said an extraordinary sitting of the chamber may need to be arranged for 28 December – three days before the end of the transition period when the UK leaves the single market and customs union. Ireland’s foreign minister, Simon Coveney, said he believed a deal would be struck despite the differences between the two sides. He said: “I think we may well be likely to go into next week on these negotiations. We’re not there yet. What I would say is the UK government understand only too well what’s needed for an agreement here. I don’t believe the EU ask is unreasonable and the EU also needs to show some compromise to accommodate many British asks. “If we can overcome those issues, in particular fish which is very emotive and very political then I think we can get a deal done. If we can’t get a deal done it will represent an extraordinary failure of politics and diplomacy.””