European Council President Donald Tusk said on Wednesday it should be known in seven or eight hours when Brexit could happen and in theory a deal could be accepted on Thursday.
Talks are underway which will decide if an agreement can be reached that would allow Britain to leave the European Union with a deal on its scheduled departure date of Oct. 31.
"Theoretically in seven to eight hours everything should be clear," he told journalists in comments broadcast on private news channel TVN 24.
"It is still undergoing changes and the basic foundations of this agreement are ready and theoretically we could accept a deal tomorrow." Tusk said.
"Yesterday evening I was ready to bet on it...today again certain doubts have appeared from the British side."
Earlier on Wednesday, Irish Prime Minister Leo Varadkar said that negotiations had so far failed to resolve issues standing in the way of an amicable Brexit, with EU sources reporting a standstill.
"Everything is going in the right direction, but you will have noticed yourselves that with Brexit and above all with our British partners anything is possible," Tusk said.