Brexit chief negotiators Michel Barnier and David Frost didn't shake hands at the end of the first round of talks on a post-Brexit relationship — but it was because of coronavirus, not because the negotiations went badly.

After years of speculation on what a post-Brexit relationship between the United Kingdom and the European Union could look like, this week more than 200 people from both sides got together to begin work in earnest.

Here are five takeaways from the first round of negotiations.

1. They got off to a good start

Never mind the handshakes, it didn't stop the two sides getting to know each other and their positions. Both teams applauded the competence and professionalism of those on the other side of the table. "We understand each other's positions. That hasn't always been the case in the past," one negotiator said.

The U.K. promised to live up to its promises on Northern Ireland — a crucial demand from the EU side. British media had reported that the Brexit team had been ordered to come up with plans to “get around” the Northern Ireland protocol in the Withdrawal Agreement, which foresees checks on goods passing from Great Britain to Northern Ireland to avoid a hard border between the latter and the Republic of Ireland.

Barnier got reassurances from the U.K. that it will keep this promise. "It was a question of trust that we needed at this point to start building our future relationship,” Barnier told reporters on Thursday.

From the EU side, Barnier made clear that nobody disputes the U.K.'s independence. The former French minister stressed that this mutual respect and not going back on earlier commitments are two possible keys to success.

And there's more. During the first round, which lasted from Monday to Thursday, there were no leaks to the media or negative spin. Given that there were more than 200 people involved and dozens of reporters eager for Brexit news, that's some achievement.

2. Not all battle lines are that far apart

Both sides stressed that the first round showed several points of convergence.

Barnier mentioned cooperation on civil nuclear power and the participation of the U.K. in some EU programs. And negotiators can even see a way forward on trade in goods, trade in services, transport and energy.

The seemingly endless debate over the past few years may have a use, as negotiators know what the other side wants and can move forward more quickly than in other free-trade agreements, according to people in the room.

3. But it's still going to be (very, very) tough

That doesn't mean an agreement will be easy. These are going to be "tough negotiations," a U.K. government spokesperson said. There are major points of divergence between London and Brussels — Barnier called them "very serious."

The main issues, according to both sides, are a level playing field, criminal justice and law enforcement, governance and fishing.

Both sides agreed to talk in parallel on the different topics because of the limited timeframe. But the EU has made very clear that agreements on fisheries and on a level playing field over the long term are two necessary conditions if there is to be a trade deal. Barnier's hands are tied by EU countries that toughened the language on these topics after the Commission's first draft of the negotiating guidelines.

The U.K. also doesn't want to apply the European Convention on Human Rights, Barnier said. According to a Downing Street spokesman, the U.K. is committed to protecting human rights but believes "that this does not require an additional binding international legal commitment."

Governance is equally tricky, because it covers all aspects of a potential deal. Whereas the U.K. wants a series of sectoral arrangements on a case-by-case basis, the EU wants one agreement. “This is not a matter of ideology, it’s a matter of being practical,” Barnier said. According to him, overarching governance would provide legal certainty and would make it easier to address new topics in the future.

And of course there's the limited timeframe. The U.K. again made very clear it will not seek an extension of the transition period, which ends in December. The EU says negotiations will have to be wrapped up by mid-October to make sure there is sufficient time to ratify the future agreement.

4. Defense is not on the table (yet)

A demand from the EU for a separate negotiating group on "Cooperation on foreign policy, security and defence" was rejected by the U.K.

Barnier said the EU remains open to discussing those subjects if the U.K. agrees to it. The Guardian reported that leaving defense and foreign policy coordination out of the negotiations is a British attempt to gain leverage in the talks.

5. The U.K. doesn't seem to be bluffing about walking away

Every good deal needs a crisette — a small crisis when one side raises its voice and threatens to walk out of the room in order to win some last-minute concessions. The U.K.'s rhetoric about leaving the EU with or without a deal at the end of the year has long been seen as a negotiating tactic in Brussels, given what the U.K. has to lose in a no-deal scenario.

But it's starting to dawn on Brussels that the U.K. is serious, EU diplomats said. Prime Minister Boris Johnson wants an independent U.K. in 2021 and if that can happen with a free-trade agreement, that's the best-case scenario. But if not, it's still set to happen. The EU will have to think twice if it wants to call Johnson's bluff.

Emilio Casalicchio contributed reporting.

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