Barnier steps up pressure on UK over Irish border
The EU's chief Brexit negotiator, Michel Barnier, gave a significant update on the state of play at a press conference in Brussels today. His opening remarks on Ireland are set out below, followed by my analysis. The original video (in French and English) is here. The subsequent Q & A (largely in French, including a question on Ireland at 24.00) is here.

Transcript

On Ireland, we focused on solutions to avoid a hard border. Any solutions must be precise, clear and unambiguous. As you know our joint report provides for three options.  
First, solving the issues on the island of Ireland through the future relationship. And this future relationship would need to avoid a hard border and protect North-South Co-operation and the Good Friday Agreement. Once again, ladies and gentlemen, it is important to tell the truth. A UK decision to leave the single market and to leave the Customs Union would make border checks unavoidable. 
 Second the UK has committed to proposing specific solutions to the unique circumstances on the island of Ireland, and we are waiting for such solutions.  
The third option is to maintain full regulatory alignment with those rules of the single market and the customs union, current or future, which support North/South co-operation, the all-island economy, and the Good Friday Agreement.  
Option one and two can only be made operational in the context of the future relationship. In the meantime, it is our responsibility to include the third option in the text of the withdrawal agreement to guarantee that their will be no hard border whatever the circumstances. This means that we must now start legally defining how this scenario would work in operational terms. There must be no ambiguity here. 
Based on the discussions this week, the Uk has accepted the neccessity of discussing how to make this full alignment scenario operational provided we discuss the other two options in parallel. And this is what we will work on in the coming rounds.  

Analysis

My interpretation is that the UK is now on tramlines towards a regulatory alignment solution, with a limited number of opportunities for diverging from that path.

One is the technical solution, Option 2. This is the approach favoured by many British Brexiters, but looks unlikely to convince the European side.

Option 1, solving the border through the future relationship, means staying in the single market and customs union for the long term, something which is unacceptable to Brexiters.

Another way out is to avoid a withdrawal agreement altogether, and accept a hard Brexit in 2019 without a deal. This would be the realisation of the 'No deal is better than a bad deal' rhetoric which the UK Government has backed away from in recent months.

If Option 3, regulatory alignment, is the ultimate solution, the question for the British Government then becomes whether to implement it on a Northern Ireland or UK-wide basis.

The former would mean a customs border between Northern Ireland and Britain, in defiance of the Government's assurances to the DUP. The latter would mean a much closer relationship for the UK than many Brexiters would be happy with, based largely on Irish considerations, and perhaps ultimately revisiting a version of option 1.