Donald Franciszek Tusk is a Polish politician who has been the President of the European Council since 2014. He served as Prime Minister of Poland from 2007 to 2014 and was a co-founder and chairman of the Civic Platform political party.
The EU's Donald Tusk said he would have "bet" on a deal 24 hours ago, but "doubts" had appeared on the UK side.
The PM is trying to get Tory Brexiteers and Democratic Unionists on board for his revised plan for Northern Ireland .
He is in a race against time to get a deal before Thursday's crucial EU council meeting.
The BBC's political editor Laura Kuenssberg said she understood the issues between the UK, EU and Ireland were "pretty much sorted", but it was still not clear whether the Northern Irish DUP were ready to sign up or not.'Hillary's ascent'
Mr Johnson has been updating his cabinet on The State of the negotiations after further talks with the DUP, whose support could be vital if Parliament is to approve any agreement.
The issue of the Irish Border - and How To handle the flow of goods and people across it once it becomes The Border between the UK and the EU after Brexit - has long been a sticking point in the negotiations.Arlene Foster met the PM for 90 minutes on Tuesday night and held further talks on Wednesday morning
The BBC's Brussels reporter, Adam Fleming , said that during the course of Wednesday there had been a shift in emphasis in The Talks away from issues around customs towards matters surrounding the so-called consent mechanism - the idea the Prime Minister came up with to give communities in Northern Ireland a regular say over whatever comes into effect.
The DUP is understood to be most concerned about this issue too. The Party also fears The Creation of a "customs Border " in the Irish Sea , which would require checks on goods between the rest of the UK and Northern Ireland .
The DUP held their latest round of talks in Downing Street on Wednesday morning. After a 90-minute meeting on Tuesday, they said.
Party leader Arlene Foster dismissed suggestions that their concerns had since been allayed.
The UK is due to leave the EU at 23:00 GMT on 31 October and Mr Johnson has repeatedly insisted this will happen, regardless of whether there is a deal or not.The View from Westminster
As I understand it, most of the issues between the UK, the EU and Ireland have pretty much been resolved, but it is still not clear whether the DUP are actually on board.
But unless and until they decide it is worth their while to come on board, then it is just too soon to definitively say this is going to be a moment.
But the DUP are not a group of politicians who are a pushover.
And this is still Something that is simply not yet in the bag.And the picture in Brussels
The expectation on the EU side is that a new Brexit deal text is pretty much ready.
They are now just waiting to hear from the UK side whether it can be signed off.
Even if this text is ready, though, even if it can be signed off by EU leaders, the EU will not yet be breathing a sigh of relief because they have been here before.
Mr Tusk suggested earlier that an agreement was still possible by the end of The Day .
"It is still undergoing changes and the basic foundations of this agreement are ready and theoretically we could accept a deal tomorrow. " he told the TVN 24 News Channel.
Irish Taoiseach Leo Varadkar also said there was still "a pathway to a possible deal" but "many issues" to resolve.'A pathway'
Thursday's EU summit is crucial because under legislation passed last month - the Benn Act - Mr Johnson is compelled to ask the EU for a delay to Brexit if he does not get a New Deal approved by MPs by Saturday.
If Mr Johnson gets an agreement with Brussels, he will ask MPs to back it and agree the next steps in an emergency sitting of Parliament on Saturday.
14:30 - The PM held a 40-minute cabinet meeting
16:30 - The PM spoke to the 1922 Committee of Tory backbenchers for about eight minutes
18:00 - Michel Barnier is briefing EU ambassadors