If the U.K. wants to build a future relationship with the EU, it needs to first rebuild trust, Michel Barnier, the EU’s chief negotiator, warned Wednesday.

“We must lay the foundations of a sustainable trust, which we need to build the future relationship with the U.K.,” Barnier said in a speech to the European Parliament. “That is the condition.”

Barnier said the EU’s goal would be to “reach a deal with the U.K.” But he added, “I would appreciate it if the British side was in the mood to reach a deal with the EU, not against the EU.”

Less than a month before the expected start of the formal Brexit negotiations, Barnier and other senior EU officials, including Council President Donald Tusk, dug in hard on their position that the talks must proceed in clearly defined sequences, with “sufficient progress” made on divorce terms before any talk of the future relationship.

“There will be no discussion of the framework for our future relations with Britain before sufficient progress is made on ensuring an orderly withdrawal,” Tusk said.

These comments, at a Parliament plenary session in Strasbourg, amounted to a stark and blunt rejoinder to the U.K.’s chief negotiator, David Davis, who rejected the phased approach during an appearance on ITV’s Peston on Sunday. “That will be the row of the summer,” Davis said, dismissing the idea that divorce terms could be discussed without looking ahead.

In comments to POLITICO after his speech to Parliament, Barnier said he was untroubled by Davis’ comments, and he expressed confidence that divorce terms would come before anything else.

“This is not a problem,” he said. “This is how we see the discussion. Until we cover the first sequence, there won’t be any discussion on other topics.” Barnier declined to speculate on the motivation of U.K. officials in rejecting the phased approach. “I say it’s clear this sequencing is a key point to create good conditions for the next step.”

In his speech, Barnier dangled some sweets for the U.K., by describing the future relationship in more detailed terms than he has previously used. “It’s not too early to start to sketch out that relationship,” he said. “It will include a free and fair trade agreement, cooperation agreements, particularly regarding universities and research, and partnership, we hope, in the areas of security and defense.”

The message seemed to be this: Take it step by step and in the right order and we all just might get where you want to go.

This insight is from POLITICO‘s Brexit Files newsletter, a daily afternoon digest of the best coverage and analysis of Britain’s decision to leave the EU. Read today’s edition or subscribe here.