Sophie in 't Veld, a Dutch member of the European Parliament who is deputy to the legislature's Brexit chief Guy Verhofstadt, said the real problem during the negotiations "lies within the United Kingdom, within the government, within the Tory party, between the parties, because there has not been any agreement over the relationship with the EU between any of them over the last two years".
A series of ministers have been seen entering and leaving Downing Street following the Number 10 announcement.
Scottish Secretary David Mundell said ministers would have to "reflect on the detail".
"The Cabinet will meet tomorrow at 14:00, to consider the draft agreement reached in the negotiating groups in Brussels and decide on the next steps", - said in the office of the Mae.
We may get Cabinet's approval and a November summit in Brussels to come.
The UK and European Union are on the brink of sealing a deal after a compromise over the backstop - the insurance policy to preventing a hard border in Ireland - was reached on Monday evening.
According to the report, the parties reached a tentative agreement on resolution of border issues between the Republic of Ireland and Northern Ireland.
It also provides for additional "deeper" provisions for Northern Ireland on customs and regulations, RTE said.
Theresa May is understood to have met with several Ministers individually on Tuesday evening, but has convened a special meeting of the Cabinet to pitch to them on the deal and encourage them to back in.
May was meeting with ministers one-on-one Wednesday morning ahead of the cabinet meeting at 2 p.m. (1400 GMT) in a bid to build agreement and stave off potential resignations.
Brexiteers lined up to condemn the deal before its details had even been officially confirmed.
"For the first time in a thousand years this place, this parliament, will not have a say over the laws that govern this country", Johnson said.
The British government supplied no immediate details on the Brexit deal which runs to hundreds of pages.
He added that "if the Cabinet agrees it, the party certainly won't".
With just months to go before the United Kingdom leaves the European Union, the two governments have agreed on a draft of what exactly that withdrawal will look like.
More troubling for May was a comment made by Northern Ireland politician Nigel Dodds of the Democratic Unionist Party.
He added: "We object to that on constitutional grounds that our laws would be made in Brussels, not in Westminster or Belfast".
"Whatever is resolved, that threat will not go away, given there are at least three more years of negotiations if there is a deal, and under those circumstances we will want to know what preparations there are for that".
EU negotiators are seeking to use a deal over the Irish border backstop to keep the United Kingdom in its customs union permanently, a bombshell leak that threatens a delicate Brexit deal has revealed.
The news comes as the European Commission revealed plans to review their visa regime after Britain's exit from the European union.
"Regulatory alignment would mean we would diverge from the rest of the UK".