8 December 2017
"Sufficient progress" has been declared. The UK-EU announcement on 8 December 2017 marks a significant step, and one that the UK government was under huge pressure to make.
The guarantee of no border checks between the Republic of Ireland and Northern Ireland ultimately implies a very high level of regulatory alignment between the UK and the EU. This may even include the possibility of a customs agreement that is very similar to the existing customs union.
While this agreement arguably saves the day for the UK government, it could make the final reckoning all the more difficult, as supporters of a hard Brexit realise that the UK might end up much closer to the EU than they thought.