British and EU officials will hold Brexit talks over the weekend amid rising speculation a deal is on the cards which could break the deadlock over the Irish border.
The EU’s chief negotiator Michel Barnier gave the green light on Friday for intensive discussions between officials to start.
Labour's shadow Brexit secretary Keir Starmer said that "every indication so far" is that a Boris Johnson Brexit would be even worse for working people.
He said it was not a deal that Labour could support.
"If Johnson does manage to negotiate a deal then we will insist that it's put back to the people in a confirmatory vote," he said.
"If he can’t – or I should say won’t – get a deal, we will take whatever steps are necessary to prevent our country crashing out of the EU."
The Prime Minister cautioned it was not a “done deal” and there was still “a way to go” if they were to get an agreement which would enable Britain to leave on October 31, as he has promised.
Mr Barnier is due to brief EU ambassadors and MEPs on Monday on progress – but time is rapidly running out if they are to get an agreement in place in time for EU leaders to sign off on it at next week’s Brussels summit.
With UK officials remaining tight-lipped, there has been intense speculation over what was said at the talks at Thornton Manor which enabled the process to move forward.
The discussions focused heavily on the issues of the customs arrangements and the proposed “consent” mechanism for the Northern Ireland Assembly.
The EU strongly objected to a proposal in Mr Johnson’s Brexit blueprint for Northern Ireland to leave the customs union together with the rest of the UK – meaning the return of customs controls on the island of Ireland.
Brussels is also concerned that a proposal in the British plan for Northern Ireland to remain tied to EU single market rules for trade in goods could be vetoed before it had even got off the ground by the Democratic Unionist Party.
There has been speculation that Mr Johnson could now try to revive a compromise proposal first put forward by Theresa May that would see Northern Ireland remain politically in a customs union with the EU, but that it would be administered by the UK.
Speaking during a school visit on Friday, Mr Johnson was adamant he would not accept any arrangement which damaged the ability of “the whole of the United Kingdom” to take full advantage of Brexit, including any new trade deals struck with countries around the world.
Meanwhile the DUP, whose support is likely to be crucial if Mr Johnson is to get a deal through Parliament, warned they would only back measures that were in the “long-term economic and constitutional interests “ of Northern Ireland.
DUP leader Arlene Foster said: “In order to secure a sensible deal for everyone it is important that the European Union understand that to maximise the prospects of agreement there will need to be a clear acceptance that the economic and constitutional integrity of the whole of the United Kingdom will have to be respected as we leave.
“As a consequence of the mandate given to us by voters in 2017 (general election) the DUP is very relevant in the parliamentary arithmetic and regardless of the ups and downs of the Brexit discussions that has not changed.”