The EU's chief Brexit negotiator Michel Barnier | Emmanuel Dunand/AFP via Getty Images Michel Barnier’s private Brexit road show The EU’s chief negotiator tells audiences a bespoke customs deal sought by UK will take a lot longer than divorce talks.

Michel Barnier says he is told by friends who have gone through a divorce that it is "painful, not pleasant, and costly." And when it comes to the Brexit split, the EU's chief negotiator says: "That's where we are."

Normally the dapper epitome of smooth diplomacy, Barnier has been delivering this uncharacteristically blunt assessment in a series of meetings and briefings for elite audiences across the Continent, according to several attendees who described the sessions for POLITICO.

Barnier's main message is that the U.K. government's demands remain highly unrealistic.

Even as British Prime Minister Theresa May is preparing to give a highly-anticipated speech in Italy on Friday, in which she is expected to restate her desire for a bespoke special relationship with the EU — perhaps with an initial financial offer included — Barnier has been telling his European audiences that Britain still doesn't get it.

"How do you build a future relationship if there’s no trust, if you haven't honored your commitments?" — Michel Barnier

In meetings with public officials, private citizen groups and business executives, Barnier has warned in recent days that the U.K. will not achieve the "special" bespoke trade deal it has demanded without lengthy negotiations after its official departure. He said the U.K. was rejecting existing models for a future relationship such as those with Norway and Switzerland and advocating a path of divergence from EU standards. The risk for the EU, he said, is that Britain would, in future, try to gain a competitive trade advantage by adopting lower social or environmental standards.

"We are not going to mix up models," Barnier has said, according to people who have heard his most recent stump speech, in which he refers to existing EU arrangements with Turkey, Norway and others. "But each model is available."

In his recent appearances, including a luncheon speech at the exclusive Cercle Gaulois club in Brussels, a briefing at the European Parliament in Strasbourg, and in other private meetings, Barnier has reiterated in blunt language that the U.K.'s refusal to commit to a financial settlement had put its future relationship with the EU in jeopardy.

"How do you build a future relationship if there’s no trust, if you haven't honored your commitments?" Barnier repeatedly asks his audiences. “I don’t know how to do that.”

While his public remarks often seem carefully constructed for British ears, with pleadings such as "we need more clarity," in private Barnier is at times considerably more direct. In one case, describing the U.K.'s obligation to the EU's current long-term budget, which runs to 2020, Barnier said: "We don’t accept to pay as 27 what has been decided at 28. It’s as simple as that. No way.”

At other times, he adopts a pedagogical approach, using a teacherly manner to walk his listeners through the complexities of the Brexit process.

Barnier's presentations are part of an ongoing campaign of public diplomacy aimed at maintaining unity on the EU side — and perhaps also laying the groundwork for a future tilt at the European Commission presidency, once Jean-Claude Juncker departs.

His main message underscores the deepening frustration in Brussels over what EU officials view as the U.K.'s muddled approach to the negotiations so far.

EU officials who once expressed hope that the U.K.'s national election in June would strengthen May's mandate and her hand in the negotiations have watched with increasing dismay as Britain has remained embroiled in internal debates. This was evidenced most recently by a shake-up among top officials at the Department for Exiting the European Union, and a new rift over Brexit that has emerged between May and Foreign Secretary Boris Johnson.

In recent days, Barnier has also met with a delegation of Portuguese diplomats, led by Secretary of State for European Affairs Ana Paula Zacarias, with members of the Scottish Parliament's European committee, and with executives of EDF, the French energy conglomerate, which had raised specific concerns about the impact of Brexit on its industry, and particularly the nuclear energy sector.

At the negotiating table, Barnier has insisted that there can be no discussion of a future relationship until the withdrawal terms are settled. But in meetings with European stakeholders, Barnier is more than willing to look ahead, and has described himself as ready and even eager to begin negotiations on a future trade relationship with Britain as soon as the European Council judges that "sufficient progress" has been achieved on the divorce terms.

But he has also stressed that a future trade accord will have to be a so-called mixed agreement that will therefore require both lengthy negotiations as well as ratification by some 40 national and regional parliaments — a high hurdle that nearly derailed a trade accord with Canada last year.

As a prop, Barnier has been showing audiences a chart, originally prepared by former U.K. Prime Minister David Cameron to illustrate the importance to Britain of the EU's single market. Barnier's negotiating team, however, has updated the graphic to show the fast-diminishing economic might of individual European countries and thereby underscore the importance of the EU as a bloc.

"The future relationship is more important than the divorce" — Michel Barnier

The chart shows that by 2050, the U.K. and France will have dropped down the list of wealthiest countries, leaving only Germany among the world's top 10 economies. "If we are not together, we will be pushed out, and thus will become spectators of what the others decide for us," Barnier has said.

On Thursday, continuing to make the rounds, he is scheduled to meet Italian officials in Rome, but aides said he will return to Brussels and will not be in Florence for May's speech.

On one point, Barnier seems to agree with his British counterparts, telling his audiences: "The future relationship is more important than the divorce." But he does not allow that the discussions of the withdrawal and the future relationship must occur simultaneously, as the British have insisted, and he has been adamant that the future trade accord will take years to complete.

"Much more time," he tells his audiences.