Britain and the European Union reached a historic deal on Brexit divorce terms on Friday that allows them to open up talks on a future relationship after the split.

Prime Minister Theresa May rushed to Brussels for early morning talks with European Commission President Jean-Claude Juncker to reach the breakthrough.

The European Commission announced that it "recommends sufficient progress" had been made by Britain on separation issues including the Irish border, Britain's divorce bill, and citizens' rights.

But EU President Donald Tusk -- who will recommend to leaders at a summit next week to open trade and transition talks -- warned that the toughest task was to come.