Even with a “deal” commencing 1 February 2020 the UK has to adapt and pass at least 6 essential bills (to be converted from EU law), discuss the Political Declaration and agree on a level playing field. All of that before ultimo 31 December 2020. And, yes, do not forget the application for a WTO membership and the upload of around 2.000 products and services. Obviously I do agree with Michel Barnier: this is mission impossible, hence it does not influence or block the exit on 31 January 2020. So be aware: the above is a hindrance to the UK and creates an undefined playfield for the EU27.