Britain and the European Union are due to outline competing visions, on Monday, of the trade deal they will seek to negotiate, following Britain’s formal departure from the bloc.
On Friday, Britain ended its 47-year membership of the EU.
The two sides now have until the end of the year to agree on their future relationship.
A transitional phase until then means little changes in the practice.
EU Chief Negotiator, Michel Barnier, is due to present the European Commission’s draft negotiating mandate at 11 am (1000 GMT).
This must be approved by the bloc’s 27 governments and the European Parliament before talks with London can begin.
Meanwhile, Britain has announced a new fast-track visa scheme for top scientists, researchers and mathematicians as it prepares a new immigration system for life outside the European Union.
Prime Minister Boris Johnson revealed the plan just days before Brexit finally takes place on January 31.
Concerns about mass migration were a driving force in the 2016 campaign to leave the EU, and Johnson has promised to end free movement with the bloc.
But he said on Sunday: “As we leave the EU, I want to send a message that the UK is open to the most talented minds in the world, and stand ready to support them to turn their ideas into reality.”
EU free movement will continue for 11 months after Brexit during a transition period designed to allow London and Brussels to agree a new future partnership.