British Prime Minister Theresa May. Photo / AP
British Prime Minister Theresa May has confirmed Cabinet has agreed a draft Brexit withdrawal agreement.
May said the Cabinet had a "long, detailed and impassioned debate".
She said the draft withdrawal agreement was "the best that could be negotiated".
"I firmly believe with my head and my heart that this is in the best interests of our entire United Kingdom," May said.
The collective agreement of Cabinet was to agree the draft withdrawal agreement and the outline future framework.
"The choices before us were difficult... but the collective decision of Cabinet was that the government should agree the document," May said.
"I know that there will be difficult days ahead. But the choice was this deal... or going back to square one."
So far May appears to have avoided resignations by senior ministers over the draft blueprint thrashed out with Brussels.
Aid Secretary Penny Mordaunt - among those closest to the edge - is believed to have demanded assurances from the Prime Minister on key points.
The text of the withdrawal agreement, and the outline political declaration on the future framework, will be published later today.
Earlier, the Prime Minister was facing a revolt from her own Cabinet after revealing a contentious Brexit deal more than two years after her country voted to leave the European Union.
Months of painstaking negotiations, marked by stalled talks, spats and late-night sessions, have finally produced a draft "withdrawal agreement". There is just one problem — a whole bunch of people hate it, reports news.com.au.
Ms May will hold a special meeting with her Cabinet on Wednesday afternoon (UK time) to "consider the draft agreement the negotiating teams have reached in Brussels" and "decide on next steps".
Hardline Brexiteers say it doesn't go far enough.
"It is vassal state stuff," said Boris Johnson, who resigned as Ms May's Foreign Secretary in July, warning her approach to Brexit would give Britain "the status of a colony".
"It is utterly unacceptable to anyone who believes in democracy. Chuck it out."
UKIP, the controversial minor party which spent years campaigning for Brexit, called the draft agreement a "betrayal" of the 17 million people who voted to leave the EU in the 2016 referendum.
"Theresa May's Brexit agreement is the worst deal in history," UKIP's former leader Nigel Farage said.
Ms May has also been condemned by the other end of the political spectrum, with some politicians arguing the proposed deal is worse than remaining in the EU.
Opponents of Brexit are still pushing for a second referendum.
Other reaction has been more mixed. Labour leader Jeremy Corbyn did not commit to supporting or opposing the deal without seeing more detail, though he is expected to eventually line up against it.
"From what we know of the shambolic handling of these negotiations, this is unlikely to be a good deal for the country," Mr Corbyn said.
"Labour has been clear from the beginning that we need a deal to support jobs and the economy — and that guarantees standards and protections. If this deal doesn't meet our six tests and work for the whole country, then we will vote against it."
Time is short. The UK is set to exit the EU on March 29 next year. Britain's parliament, the European parliament and all 28 nations in the bloc have to approve any deal before then. Otherwise, there won't be one.
The first challenge Ms May faces is winning over the Brexiteers in her Cabinet on Wednesday. Should she fail to do so, the terms of the deal will have to be renegotiated, wasting precious time.
Say she succeeds. Then there will be a meeting of the 28 member states of the EU. Ambassadors from all of them are due to convene in Brussels tomorrow. They are likely to approve the deal, given it has been ironed out by their lead negotiator Michel Barnier.
The next step is the hardest. Ms May will need a majority of MPs in the UK's parliament to vote in favour of her agreement.
Not only is she leading a minority government, but a large number of MPs in her own party will inevitably oppose the deal for being too soft.
Fail, and she could face the prospect of a no-confidence motion, and her government falling.
Succeed, and she will need to pass a law making the deal official before heading back to Brussels and asking the EU parliament to ratify it.
A spokeswoman for the EU negotiator Mr Barnier has urged caution, saying the deal is not yet finalised and everyone should "take stock" on Wednesday.
Britain's newspapers certainly aren't getting ahead of themselves. Most have published Wednesday papers focusing on the potential "revolt" in Ms May's Cabinet.
The main obstacle in negotiations has been how to ensure there are no customs posts or other checks along the border between Northern Ireland, which is part of the UK, and Ireland, which is a member of the EU.
Britain and the EU agree there must be no barriers that could disrupt businesses and residents on either side of the border and undermine Northern Ireland's hard-won peace process — but they have differed on how to achieve that.
Irish national broadcaster RTE said the draft agreement involves a common customs arrangement for the UK and EU to eliminate the need for border checks, with special provisions for Northern Ireland and a review mechanism to oversee its functioning.
A sticking point in talks has been Britain's insistence that any such customs arrangement must be temporary. The EU says that in order to guarantee an open border, it can't have a time limit.
If there is no final agreement soon, British businesses will have to start implementing contingency plans for a "no-deal" Brexit — steps that could include cutting jobs, stockpiling goods and relocating production and services outside the country.
Even with such measures in place, the British government says leaving the EU without a deal could cause major economic disruption, with gridlock at ports and disruption to supplies of foods, goods and medicines.
The consequences for Ms May's leadership would be equally dire.
Putin signed a decree that enables nuclear weapon use against non-nuclear states.