1. The cabinet will meet next week to agree its Brexit negotiating position. Theresa May told ministers on Tuesday to “stand by their diaries” and re-read their previous Brexit papers for the crunch meeting, which is expected to take place on either Monday or Tuesday. There is also likely be a warm-up conference call over the weekend for the prime minister to “sell progress” to colleagues in an attempt to sign them up to an agreed position.

2. Resolving the Irish backstop is the critical question. The backstop was intended to be an insurance policy to avoid a hard border in Ireland if no long-term free trade agreement could be signed by the end of the transition period in 2020. May’s desired version has the UK agreeing to keeping the whole country in a customs union if needed. However, hard-Brexit Conservatives are concerned that without easy exit clauses, the temporary arrangement could become permanent.

As a result, Dominic Raab, the Brexit secretary, Jeremy Hunt, the foreign secretary, and Sajid Javid, the home secretary, have all said they want the UK to be able to exit the backstop unilaterally.

But Geoffrey Cox, the attorney general, warned cabinet members on Tuesday that that may not be legally achievable, and he and Raab were tasked to draft a workable exit mechanism for the special cabinet next week.

3. Ireland and the European Union will only accept a backstop that ends by mutual agreement. Leo Varadkar, the Irish prime minister, told May in a phone call on Monday that “the outcome of any such review could not involve a unilateral decision to end the backstop”.

The expectation is that Raab and Cox will produce a draft backstop with a mechanism that ends mutually for next week’s meeting.

Michael Gove, the environment secretary, also demanded that cabinet see the accompanying legal advice in full; not least because if ministers are to go along with a mutual exit mechanism they will need the advice as cover.

4. The precise wording of the backstop will be intensely scrutinised. Political anxieties about the wording of the backstop intensified on Friday after the leak of a letter from May to the Democratic Unionist party, which said the EU still wanted an additional “backstop to the backstop”.

This would tie Northern Ireland to the EU’s single market and customs union if the UK-wide customs arrangement failed, although May told the DUP in the letter, sent on Tuesday, she would never allow it to “come into force”. That implied it would still exist buried in the backstop text.

The DUP leader, Arlene Foster, said this raised “alarm bells”. May needs the DUP’s 10 MPs to get her plan ratified in the Commons.

5. There is a long way to go. If the cabinet is happy, the draft withdrawal agreement – including the backstop – could be published next week. It is expected to be accompanied by a draft political declaration, an aspirational document setting out the UK’s future trading relationship with the EU.

The deal will then have to be signed off at an EU summit, ideally in late November, before being presented to MPs for ratification in December. Ministers hope there will be “a new dynamic” once the deal is public – there will be an intense lobbying campaign arguing that May’s deal is in the “national interest” and that the alternative – no deal – would be an economic disaster.

However, there remains acute scepticism in Tory ranks as shown by the surprise resignation of the rail minister, Jo Johnson. Steve Baker, a key figure in the European Research Group, said his group was ready to vote down May’s deal if the political declaration did not allow the UK latitude to pursue an independent trading future from the EU. If MPs were to block May’s plan, it would provoke a “profound political crisis”, he added.