Theresa May will meet Donald Tusk face-to-face on Thursday for the first time since she began Britain’s formal departure from the European Union. The meeting at May’s Downing Street office, at 1 p.m. London time, will give the pair the chance to discuss how negotiations will proceed. Publicly, both the prime minister and the European Council president have said they want to maintain good relations after Britain departs. But they disagree about the order in which things should be discussed. “We will be talking about the start of the negotiations, how we’re going to take these negotiations forward,” May told reporters after a speech in Nottingham. “We’ve said very clearly we want to maintain a deep and special partnership with the EU, and I think that has been reciprocated.” Substantive talks can’t begin until May 22, when EU governments are set to approve the final negotiating directives. In draft guidelines circulated to the bloc’s 27 other capitals on Friday, Tusk said a free-trade agreement can only be finalized after the U.K. has left the bloc. He said later he hoped that “sufficient progress” will be made by this fall to allow preliminary trade discussions to start. May wants parallel talks on the exit and future relationship. May said she’d also talk with Tusk about “how we can ensure, within the timescale that we’ve got, that we can deliver a deal that is going to work for the people of the United Kingdom.” She added “I believe that will also be a deal that will work for the EU as well.” Another sticking point is whether security cooperation should be part of the negotiations. May insisted this week that she had been right to raise the issue when she triggered Brexit, because it was important to establish how systems would work once the U.K. has left the EU. But Tusk has said he won’t allow it to be a bargaining chip for a trade deal. May has also said she wants an early agreement to secure the rights of EU citizens living in the U.K. and those of British citizens in the EU.