The EU's chief Brexit negotiator has dismantled Boris Johnson's border proposals point-by-point in a comprehensive speech to the European Parliament.
Michel Barnier said that "to put things very frankly ... we're not really in a position where we're able to find an agreement".
He added that British proposals "have led to three serious concerns": that they did not prevent a customs border, that they were not actually ready or "legally operational", and that they could be unilaterally scrapped by Stormont and even never actually come into effect act all.
Mr Barnier said the plans represented "a significant risk to the integrity of the single market" and warned: "Time is pressing. We are one week away form the European Council summit and just a few weeks away from the date of October 31".
His warning comes ahead of high-level talks between himself and Steve Barclay, the Brexit Secretary, who is due to visit Brussels again on Thursday.