Michel Barnier has sought to break the deadlock in what he described as the final “few hours” of the post-Brexit trade talks with a new proposal on EU fishing access in British waters, after Boris Johnson called on Brussels to move to seal a deal. After meetings with aides to the EU’s heads of state and government and fisheries ministers, Barnier was locked in late-night discussions with the UK negotiators led by David Frost, at what Barnier described as a “moment of truth”. Talks are expected to continue into Saturday, with UK sources downplaying the chances of a breakthrough following Barnier’s move. The two sides are at loggerheads over whether the EU will be able to impose tariffs on British goods should the UK close its seas to European vessels after a new transition period of unspecified length, with less than two weeks to go before the end of the current transition period. There are also major differences over how much the UK should be able to catch in its own waters in the future, with Barnier only edging up his offer from 15% to 18%. The UK is demanding that 60% of the €650m in EU turnover from fish caught in British waters is taken back. Boris Johnson had conceded earlier on Friday that it would be “difficult at first” if the UK were to be forced to trade on World Trade Organization (WTO) terms from 1 January, but insisted it was time for the EU to move on what is now the biggest stumbling block. He said: “Our door is open. We’ll keep talking. But I have to say that things are looking difficult. And there’s a gap that needs to be bridged. We’ve done a lot to try and help, and we hope that our EU friends will see sense and come to the table with something themselves. “If that doesn’t happen then come 1 January we will be trading on WTO terms. An event that obviously has been four and a half years in the making … Yes it may be difficult at first, but this country will prosper mightily, as I’ve said many, many times, on any terms and under any arrangement.” Johnson said “no sensible government” could sign up to a deal that did not allow the UK to retain control of its laws and its fishing rights. As businesses raced to get stockpiles delivered ahead of the establishment of customs barriers on 1 January, long queues formed on the French and British side of the Channel, with drivers reporting full ferries and six-hour waits in Calais. Earlier, Barnier said the main obstacle to a deal was over whether Brussels would be able to hit British goods with tariffs if the government closed its fishing waters to EU fishing fleets in the future. With the European parliament having said it needed agreement by midnight on Sunday for it to be able to give its consent in a vote this year, the EU’s chief negotiator said the nine months of trade talks had reached the “moment of truth”. Barnier said it would only be fair for Brussels to be able to put tariffs on UK goods, and fisheries products “in particular”, in a possible sign of EU flexibility on the issue. The UK is concerned that Brussels will strike at non-fishing products in such a scenario. The government has said that after a transition period of three years it wants exclusive access to the zone six to 12 nautical miles from the British coastline, where French and Belgian fleets have fished for centuries. In a speech to the European parliament, Barnier told MEPs: “It’s a question of whether the UK will leave in a few days – 10 days or so – if they’re going to leave the single market and the customs union with an agreement or without an agreement. It’s the moment of truth. “We have very little time remaining, just a few hours to work through these negotiations in a useful fashion if you want this agreement to enter into force on 1 January.” Barnier warned Downing Street that the time had come “when decisions need to be taken”. “When it comes to access to markets without tariffs and quotas and the UK would like to regain its sovereignty over fisheries, to be able to control access to its waters and, as I’ve said on many occasions, I’ll reiterate that here: we can accept that and we respect that,” he said. “But if following a critical period of adjustment that is deemed necessary, if the UK then wants to cut access to these waters for European fishermen, at any given time, then the European Union also has to maintain its sovereign right to react or to compensate by adjusting the conditions for products, and especially fisheries products to the single market. And that is where we come up against one of the main hurdles of the negotiations at the moment, fisheries being part and parcel of the economic partnership.” Barnier, a former French fisheries minister, said there was a fundamental issue of fairness that the EU would not back down on. About 75% of UK fish exports, including the most valuable species such as herring, cod, shellfish, mackerel and salmon, goes to the EU market.