Prime Minister Theresa May’s proposed EU Withdrawal Agreement was published on Wednesday night following the announcement that the Cabinet had approved the draft.
The 585 page long agreement has led to seven resignations, including Brexit Secretary Dominic Raab and Work and Pensions Secretary Esther McVey.
So what is in this deal to cause it? And what does it mean for the future of the UK? Here are the key points.
A transition (or implementation) period is due to begin when the UK leaves the European Union on March 29, 2019. It would last 21 months and during which the UK would continue to follow the rules of the European Union. That includes remaining within the single market and under the jurisdiction of the European Court of Justice until December 2020.
The transition period would also be extendable, if both the EU and UK decide they need more time. The document does not specify how long the transition could be extended for. The date has been left blank, with the document simply saying that the Joint Committee may take a decision "extending the transition period up to [31 December 20XX]."
The Divorce Bill
The UK agrees to cover contributions to staff pensions and commitments to EU programmes for the period up until 2020.
The bill has previously been estimated to be costing the UK £39 billion.
The “backstop” would be implemented only if there was no long term trade agreement and no extension of the transition period.
If the backstop is needed, it will be in the form of a UK-wide customs union on a temporary basis. The draft agreement describes this as a "single customs territory".
However, under the agreement Northern Ireland would be closer aligned to the EU than the rest of the UK.
Freedom of movement will stop at the end of the transition period, but no other immigration rules were included in the agreement. This allows the UK to decide its own rules once the transition period is over.
The existing rights of EU citizens living in the UK have already been guaranteed and the same applies for Britons living in the EU.
Fishing is the only industry to be excluded from this possible customs arrangement.
The proposal simply states that "the Union and the United Kingdom shall use their best endeavours to conclude and ratify" an agreement "on access to waters and fishing opportunities".
Leaving the arrangement
Like the backstop, how to leave this temporary measure was one of the last issues to be agreed in the negotiations.
Under Mrs May’s agreement the UK would not have the unilateral power to bring the backstop to an end. The backstop would only end if "the Union and the United Kingdom decide jointly" that it is no longer necessary.