Progress - But Not "Sufficient Progress"

Following Theresa May's speech in Florence, there had been hopes in some quarters of a breakthrough in the Brexit negotiations, allowing talks to progress beyond the 3 issues which the EU has identified as the focus of the first phase of discussions.  Indeed, the EU has broadly welcomed the Prime Minister's more positive tone.  However, its chief negotiator, Michel Barnier, has indicated that "we are not yet there in terms of achieving sufficient progress" – "sufficient progress" being the benchmark for the talks to move onto other issues, including, critically, trade and the shape of any transitional arrangement. 

Whilst the EU's somewhat rigid approach to the first phase of negotiations is no doubt a source of considerable frustration to the UK negotiators, "sufficient progress" is a phrase which allows for "constructive ambiguity";  in particular, it does not require the talks to have resolved all the first phase issues fully and the final decision on whether it