Analysis: Three scenarios
By BBC political editor Laura Kuenssberg
The worst-case scenario for Downing Street is that EU leaders are so fed up with the UK position and what they see as the lack of reality, that on Thursday, they formally say they will hold a no-deal summit in November.
That would switch them on to a track that would be hard to get off once in motion.
One EU source expressed disbelief that Theresa May thought she could turn up on Wednesday with nothing new. It was simply crazy, in their view, to suggest that the ball can be lobbed back into the EU court.
The best case - and it seems right now unlikely - scenario is for the EU to say that there is a deal in reach, so let's get a date in the diary for the sign-off next month.
What seems more likely is a holding position. EU leaders could give some kinds of vague noises that both sides still want to pursue negotiations, so that the talks can get going again.
One Brussels source said that while it is "time for choices", they could give the prime minister space and time to build a majority at home for a deal.