The government has been reassured by indications that some Eurosceptics are prepared to pay a little more as the price for ensuring Britain heads out of the exit door.
That scenario would effectively require Northern Ireland to remain in the single market and the customs union.
Britain's Brexit Secretary David Davis however has moved to have official Brexit date in enshrined in United Kingdom law.
That is something which the Conservatives and DUP have said they can not accept as it would effectively create a border between Northern Ireland and the rest of the UK.
Ireland has consistently argued that the United Kingdom remaining in the customs union would be the easiest way to avoid a new border.
Before his meeting with the Brexit Secretary, Mr Barnier said the moment was approaching for a "real clarification" of Britain's position on issues like citizens' rights, the Irish border and the UK's financial settlement.
The EU circulated a document to a meeting of EU diplomats Wednesday that called for Northern Ireland to maintain the rules of the customs union and single market after Brexit.
The paper which was originally reported in The Financial Times, notes that "an important part of political, economic, security, societal and agricultural activity on the island of Ireland now operates on a cross-border basis, underpinned by joined European Union membership of the European Union and Ireland". "A key priority remains to preserve the sovereignty of our courts", he said. "We have consistently taxes and funding and enterprise and entrepreneurs and customs and borders but really children are the [.] people who are going to be living in this new reality in the future and we really need to take their voices and their rights seriously", he said.
"But we need to see flexibility, imagination and willingness to make progress on both sides if these negotiations are to succeed", he added.
He said: "When it comes to the border between Ireland and Northern Ireland, what we have all agreed to is that there shouldn't be a hard border, there should be no physical infrastructure along that border and that there should be no return to the borders of the past".
Kerr said the British government has misled voters into believing the process is unstoppable.
Without this, the European Union is insisting that talks on future relations can not take place.
Mr Brokenshire said he found it "difficult to imagine how Northern Ireland could somehow remain "in" while the rest of the country leaves".
The Democratic Unionist Party (DUP) meanwhile has repeatedly warned that it will not accept any deal that undermines the union between Britain and Northern Ireland.
He did suggest there could be some aspects of agri-food that were handled on an all-island basis, but Irish sources say he did not fully explain how far that would go, or how it would avoid a hard border.
Ambassadors from the EU-27 this week discussed internal deadlines in preparing for the December summit, and will take stock of the progress of Brexit talks on 20 November.
But its articulation of the customs union and single market issues are likely to prompt fierce resistance from the DUP.