The Prime Minister is due to hold a special meeting today to approve the draft EU divorce bill she has negotiated with Brussels.
It is understood the document has been agreed at a technical level by UK and EU officials, according to reports by the BBC.
However, exact details of what the future holds for both parties in the agreement have yet to be released.
Mrs May was said to have held one-on-one meetings with ministers in Downing Street yesterday evening as she prepares for the political fight of her life in getting the seal of approval from her Cabinet.
The pound has reacted positively to the Brexit breakthrough, and was trading at €1.52 against the euro earlier this morning.
As of just after 8:30 GMT, the pound had moved back slightly to €1.49.
Mrs May and her Cabinet will gather today at 14:00 GMT, shortly after Prime Minister’s Questions.
But the road ahead could be perilous for the Prime Minister, as reports suggest she has risked infuriating Brexiteers by allowing customs union membership to become the “basis of the future relationship” with the EU.
It is believed both sides have devised a working solution for the Irish border issue, which has proved to be the main point of contention throughout the negotiating process.
But in a bid to please Northern Ireland’s Democratic Unionist Party and Brexiteer MPs, the Prime Minister may have signed up to the possibility of a permanent customs union with the EU, unless a better deal is reached by the end of the transition period in December 2020.
Senior Brexiteers have since come out calling for the deal to be rejected as they took aim at Mrs May.
Former foreign secretary Boris Johnson has already said he would vote against the reported agreement over the Northern Ireland backstop, describing it as leaving the UK “in captivity” of the EU.
While Jacob Rees-Mogg told BBC Newsnight it was “not what we were promised”.
The Democratic Unionist Party DUP – who Mrs May will heavily rely on to get the deal passed through Parliament – has said the Brexit deal could lead to the break-up of the UK.
Speaking on BBC Radio 4’s Today programme, the party’s chief whip Sir Jeffrey Donaldson warned the deal in the “long term” leave Northern Ireland closely aligned with the EU and could increase support for Scottish independence.
He added: “This is not the right Brexit.”
Mrs May needs the approval of her Cabinet in order to sign off the agreement, of which the details of the 500-page document will then by published.
EU leaders would then need to pour over the details before giving their seal of approval, ahead of a parliamentary vote before the end of the year.