Talks between Dominic Raab and Michel Barnier have broken up, with no substantial progress having been made.
And with the exception of an agreement, there will be no more negotiations before EU government heads meet at the European Council on Wednesday.
With the important draft of the withdrawal agreement now not expected to be published before then,the risk has seriously risen of Brexit talks flopping at the council.
One cause of the impasse is that Barnier does not yet understand what long-term, steady-state customs arrangement Theresa May actually wants.
So right now the nature of Brexit hinges mainly on what May can get through her Cabinet and parliament.
Her fear is there would be no deal available that would command a consensus or majority among ministers and MPs or be consistent with how she interprets the referendum result.
It will be a stressful few days for her and the whole nation.