[Cherie]

European Union leaders have unanimously agreed to tough negotiating guidelines for Brexit talks with the UK, suggesting that they will demand Britain agrees on payments to the bloc before considering a new trade deal.

The heads of the remaining 27 countries agreed to adopt the draft guidelines issued by Donald Tusk last month less than 15 minutes into a special summit in Brussels on Saturday. The European council president tweeted that a “firm and fair political mandate” for the negotiations was now ready.

The EU is expected to demand that Britain resolves the key divorce issues of citizens’ rights, the divorce bill and the Irish border before any talks on a future trade deal between the UK and the EU can begin.

Tusk, the president of the council, whose members comprise the EU states, said ahead of the meeting on Saturday: “We all want a close and strong future relationship with the UK. There’s absolutely no question about it. But before discussing the future, we have to sort out our past. We will handle it with genuine care, but firmly. This is, I think, the only possible way to move forward.

“We also need solid guarantees for all citizens and their families who will be affected by Brexit, on both sides. This must be the number one priority for the EU and the UK.”

The EU has taken some confidence from the fact that Theresa May has not recently repeated her claim that “no deal is better than a bad deal”, despite being pushed to do so by politicians in favour of a hard Brexit.

“We are convinced that no deal is in no one’s interest. We appreciate the fact that the tone of the debate in the UK on this issue has changed,” said a senior EU official on Friday.

Asked to respond to claims from the prime minister on the general election campaign trail that member states were preparing to “line up to oppose us”, one senior EU diplomat admitted: “She’s right. She should not underestimate the commitment to unity.”

The leaders are also set to back automatic EU membership for Northern Ireland if it votes in the future to reunify with Ireland, and will call for Spain to have a say over any deal that affects Gibraltar in a document detailing the European council’s negotiating guidelines, which will set the broad political goals of the 27 states when talks start in June.

During a working lunch to approve the position drafted by officials, leaders will furthermore discuss for the first time the relocation of EU medical and banking agencies that are currently based in London. The European commission president, Jean-Claude Juncker, along with Tusk, is expected to offer an indication of the selection criteria that will be used to choose between the many states bidding.

Dublin presented its request over Northern Ireland and the implications of reunification in the future during a meeting of EU ambassadors last Wednesday, it is understood. “There was no discussion, because there was no need for a discussion”, an EU source said. “There is total agreement.”

The first of the key issues the EU guidelines say Britain must resolve, however, is the fate of 3 million EU citizens living in Britain and 1 million Britons on the continent, and what happens to their rights to work and claim benefits abroad.

Leaks suggest the leaders believe that any EU national who moves to the UK before the withdrawal date should have all the rights they would have expected in the past, including that of being able to enjoy permanent residency status once they have lived in the UK for five years, no matter when that period of residence begins.

The EU27 will also call for action to avoid a “hard border” between the Republic of Ireland and Northern Ireland, as fears persist that Brexit could undermine the peace process.

The most contentious issue, however, is likely to be Britain’s exit bill, estimated at around €60bn (£50.4bn), covering financial commitments made by the bloc during Britain’s time as a member.

Only once “sufficient progress” has been made in the talks on these issues, will the European council countenance talks about the future relationship.

Asked what sufficient progress would mean in relation to the UK’s divorce bill, a senior EU diplomat said the European council’s guidelines were quite explicit about what would be expected and that there would be little “wiggle room”.