Yesterday's announcement from the EU offers a fresh chance of a Brexit deal, a withdrawal agreement and a transition period to the end of 2020. However, it remains to be seen whether Johnson has the numbers to get the deal through Parliament tomorrow.

This agreement would address immediate concerns about the impact of a no-deal exit on 31 October and allow the focus to move to the future relationship. However, we should remember that we have been here before: Theresa May brought a deal back from Brussels one year ago but it foundered in the UK Parliament three times. Today's deal still needs approval from each of the UK Parliament, the EU27 and the European Parliament.

Assuming the deal is approved by EU27 leaders at the EU Summit taking place this afternoon, it currently appears that the deal will be put to the House of Commons for a "meaningful vote" this Saturday, 19 October 2019. If the House of Commons votes against the new deal on Saturday, the Benn Act requires the Prime Minister to request an extension to the Article 50 period until 31 January 2020. It would then be for the EU27 to consider such a request, presumably in a further extraordinary EU Summit next week or the week after. Following the announcement of the deal yesterday afternoon, the EU Commission President has reportedly ruled out the EU granting a further extension beyond 31 October. While this will certainly raise the temperature of the debate in the House of Commons on whether to approve the deal or risk a no-deal Brexit, ultimately whether to grant an extension will be a question for EU27 leaders in the event the deal is rejected.

Following these developments, it remains to be seen whether the prime minister can get the deal through Parliament (although the Democratic Unionist Party, whose MPs are thought to hold considerable sway among certain Brexit-leaning Conservative MPs on matters relating to Northern Ireland, has said it does not support the deal as it stands). And, if he does not, whether the EU is willing to approve a further extension to the Article 50 period, and on what terms.