Theresa May meeting with EU Council President Donald Tusk in London in 2018 | WPA pool picture by Leon Neal via Getty Images EU drops ‘neighborly cooperation’ hint to departing UK Iceland’s prime minister says ‘we would be happy to talk’ with the UK.

After Thursday’s lengthy Brexit talks, European leaders dropped some not-so-subtle hints in London’s direction that sticking close to the EU club — even if not actually within it — comes with perks.

The European Council on Friday began its second summit day with a celebration of European cooperation, marking the 25th anniversary of the European Economic Area — the group of countries that includes all the EU members plus Norway, Liechtenstein and Iceland.

It came on the morning after EU leaders granted a short extension to Brexit day, throwing a lifeline to MPs in the House of Commons who want to steer the government toward a closer post-Brexit relationship with the EU.

Speaking about the EEA’s achievements, Council President Donald Tusk lauded “the spirit of neighborly cooperation.”

“We should never take this for granted,” he told the Council and the leaders of Iceland, Norway and Liechtenstein, who had also travelled to Brussels to mark the anniversary.

“Even though some of us are outside the European Union, we do have a great cooperation" — Norway's Prime Minister Erna Solberg

“In a world of resurgent nationalism and authoritarianism … you have stood firmly on the side of wisdom, the rule of law, cooperation, and deeper integration among our nations,” he added.

Martin Selmayr, secretary-general of the Commission, called the EEA "a well tested, successful model for close economic integration."

Arriving at the Council, the guest leaders also offered some words of advice for Britain.

Norwegian Prime Minister Erna Solberg noted that cooperation with the EU and being a non-member were not mutually exclusive.

“Even though some of us are outside the European Union, we do have a great cooperation," she told reporters.

Iceland’s Prime Minister Katrín Jakobsdóttir stressed that working together with the bloc has been “very beneficial” and said the U.K. ought to think about “how to proceed” in terms of cooperating with Europe.

“We have valued the importance of European cooperation very much, even though we stand outside the EU,” she said. “That’s something the U.K. must think about — what the values of European cooperation are.”

Asked if she would welcome the U.K. into European Free Trade Association — made up of the three EEA countries plus Switzerland — Jakobsdóttir noted that the four EFTA states had to abide by the four freedoms, including freedom of movement, which Theresa May has pledged to end.

But Jakobsdóttir added: “We would be happy to talk about that if that’s something the U.K. wants to talk about.”