Germany, France and Italy have said the EU will not hold talks with the UK on Brexit until Article 50 has been triggered.
Speaking alongside French President Francois Hollande and Italian Prime Minister Matteo Renzi in Berlin, German Chancellor Angela Merkel described the UK’s vote for a Brexit as a "very painful and regrettable decision".
She said: "We are in agreement that article 50 of the European treaties is very clear – a member state that wishes to leave the European Union has to notify the European Council…
"There can't be any further steps until that has happened. Only then will the European Council issue guidelines under which an exit will be negotiated.
"That means that, and we agree on this point, there will be neither informal nor formal talks on a British exit until the European Council has received the... request for an exit from the European Union."
Hollande spoke of the importance of negotiating the UK’s exit as quickly as possible, adding: “There is nothing worse than uncertainty.”