The prime minister said that he would pursue a Canada-style free trade agreement with the European Union and if one is not agreed is prepared to trade with the bloc on World Trade Organization rules instead, saying that with or without a deal, "I have no doubt Britain will prosper".
With Britain's formal exit from the bloc on Friday night, many Britons had hoped to finally put the Brexit nightmare behind them. The EU will also lay out its negotiating stance today.
"There will be two conditions which will be very clear in this trade agreement: we want an agreement on fisheries, which will be hard, on reciprocal access to waters and markets for British and French fishermen", Barnier told French broadcaster LCI on Sunday.
The UK has always been a member of the WTO in its own right but while it was a member of the European Union it was represented in talks by the European Commission.
For now, Mr. Johnson is hanging tough, arguing on Monday that rather than accept alignment with European rules, he would prefer a trading relationship similar to that of Australia, which has no free trade agreement with the European Union. He continued: "There are other issues where I think that I've heard a certain amount of [hysteria]..." However, we believe that a de facto/artificial extension could be achieved by agreeing that the divergence would happen slowly over time, as part of a more comprehensive deal.
Businesses will have to take the same steps to prepare for the end of the Brexit transition period whether Britain strikes the Canada-style trade deal it is seeking, or a less comprehensive deal, Mr Johnson's spokesman said.
This totally contradicted the Political Agreement he signed along with the Withdrawal Agreement a year ago.
The EU is constantly saying that it took seven years to arrange the Canada deal, ok it did; but you've now got another country that wants to adopt nearly exactly the same thing, in which case, as Boris Johnson has said, it's oven-ready, it's off the shelf, let's just move on with that.
"We'll work to avoid that, but if we can't manage a deal by the end of the year, there will be a cliff edge on many fronts", Mr. Barnier said.
Mr Johnson said in a speech: "We want a comprehensive free trade agreement similar to Canada's but in the unlikely event that we do not succeed then our trade will have to be based on our existing Withdrawal Agreement with the European Union".
Johnson will say he expects it would be a "highly unlikely event" that the United Kingdom will not succeed in striking an arrangement like Canada, but that "in either case, I have no doubt that Britain will prosper". "It would do very little to remove other frictions in trade", Mr. Lowe added.
"You can not accuse us of a lack of ambition", he told a news conference in Brussels.
Downing Street accused the European Union of reneging on promises in insisting EU courts have jurisdiction should any disputes over European Union law arise following the Brexit deal. The EU has however picked up the wording of the Political Declaration in its draft negotiating mandate, and sees this wording as supporting the position it has set out.
In a sign that this too could be yet another flashpoint in the negotiations, Mr Johnson told reporters: "The UK will be negotiating on behalf of the entire UK family and that certainly includes Gibraltar and the sovereignty of Gibraltar remains, as everybody knows, indivisible".