EU leaders are refusing to negotiate face-to-face with Boris Johnson at today's summit in Brussels, dashing hopes that a Brexit deal could be struck at the meeting.

"Brexit negotiations at 28 [leaders] are not foreseen in the treaty, so we will stick with this treaty reality," a senior EU official said ahead of the gathering of leaders.

"I believe that by now it is obvious for everyone that Brexit negotiations take place not during the summit. On the other side of the street, we have our negotiator [Michel Barnier] and everyone trusts him and we are happy with his performance."

The senior official added that Mr Johnson would be allowed to address his fellow leaders if he chose, but that the 27 presidents and prime ministers would then continue without him for the main discussion.

"The meeting will be in Article 50 format: this is the format for 27 members only. Prime minister Johnson will have a chance to address the 27. Of course it will be for him to decide if it is a good idea or not, whether he wants to address the leaders or not. But the possibility will be there."