- Video report by ITV News Europe Editor James Mates
Theresa May has been told by Europe's leaders it is the "last call" for her to set out her plans for Brexit.
EU figures issued the warning in the hope that the bloc and the UK can achieve a future relationship deal in October.
Europe's leaders demanded clarity from Mrs May as their impatience over the Prime Minister's divided Cabinet became clear.
The leaders of the remaining 27 EU nations issued a joint call for "realistic and workable" proposals from Mrs May.
At the close of a summit in Brussels, European Council President Donald Tusk said there was a "great deal of work ahead" on Brexit and the "most difficult tasks are still unresolved".
He said "quick progress" was needed in order to reach a deal at the October summit and "this is the last call to lay the cards on the table".
French President Emmanuel Macron said the remaining 27 EU member states "can no longer wait" for progress on Brexit.
Belgian Prime Minister Charles Michel pointed to Mrs May’s domestic political difficulties, saying the British gave the impression of negotiating with each other, rather than the EU.
Brussels' chief Brexit negotiator Michel Barnier also warned that time was short and suggested an extra round of negotiations on Monday to help reinvigorate the talks.
Mr Barnier said "huge and serious divergence" remained over issues relating to Ireland and Northern Ireland.
The prime minister said she hoped a new phase in the Brexit talks would be possible after the publication of the government's White Paper calling for negotiations to speed up and intensify once the document is published.
Details of the White Paper setting out the UK's plans for issues including trade and customs are expected to be thrashed out by Cabinet ministers at next Friday’s Chequers away-day.
Mrs May's participation in the European Council summit ended in the early hours of Friday morning after a marathon session on proposals to address the migrant crisis.
Leaving the summit in Brussels, she said: "We are going to be publishing our White Paper shortly and I want to see the negotiations accelerating and intensifying thereafter."
Asked whether the White Paper would provide "realistic and workable" proposals, a Downing Street spokeswoman said: "Yes."
The Prime Minister is expected to meet key players in Europe in an effort to boost support for the White Paper, with Germany’s Angela Merkel confirming she was expecting a visit from Mrs May.
The 27 remaining EU leaders swiftly agreed a joint position on Brexit in Mrs May’s absence on Friday.