Brexit: Where is the EU–UK Relationship Heading?

I am delivering this lecture almost two-thirds of the way between the June 2016 EU referendum and the day the UK is scheduled to leave the EU, yet the long-term relationship between the UK and the EU still remains unclear. The basic elements of the Article 50 Withdrawal Agreement and the transition arrangements seem to be in place (except for the issue of the Northern Ireland-Ireland border), but there has been far less discussion of the post-transition 'future relationship' between the UK and EU27. The basic options for the future relationship have been known for some time: such as a 'soft' form of Brexit represented by the UK remaining in the European Economic Area (EEA); a 'hard' form of Brexit represented by the UK remaining in the EUropean Economic Area (EEA); a 'hard' form of Brexit represented by the UK leaving the EU's single market and signing a free trade agreements similar to the EU's agreements with Canada or South Korea; or 'no deal' and the UK trading with the EU as a member of the World Trade Organization (WTO). The British government has started to clarify its preferred outcome: what the Secretary of State for Leaving the EU described in December 2017 as a 'Canada plus plus plus' agreement. Only the basic features of the future relationship need to be agreed before March 2019, and the final agreement and ratification will only take place after the UK has become a third country. Hence, the final settlement is unlikely to be known before late 2020 at the earliest.