UK Prime Minister Theresa May is likely to trigger the formal process of leaving the European Union early next year, according to a top EU official.
European Council President Donald Tusk said May had told him the UK could be ready to begin talks by February.
The BBC's Tom Bateman says this is the clearest sign yet of when the two-year withdrawal process may start.
May's office said it would not be launched this year, but did not confirm Tusk's account.
Formal negotiations over the withdrawal cannot begin until the UK triggers Article 50 of the Lisbon Treaty, the formal mechanism for leaving the union.
The timing of the process has so-far been clouded by uncertainty, with no clear signal from May's government on when it would begin.
There is also confusion over the nature of the the UK's future relationship with the bloc, especially whether it intends to remain a member of the single market.
Tusk spoke from the Slovakian capital, Bratislava, where Europe's 27 other leaders are gathered for an informal summit without the UK.
Speaking about a meeting with the British PM in London last week, Tusk said: "Prime Minister May was very open and honest with me.
"She declared that it's almost impossible to trigger Article 50 this year but it's quite likely that they will be ready maybe in January maybe in February next year."
European Commission President Jean-Claude Juncker insisted that the UK could not get access to the single market without accepting the free movement of workers.
May has indicated that in any negotiations, her government would insist on placing curbs on EU citizens entering the UK.