Give me Brexit deal I can 'defend' at home, British Prime Minister tells EU

Addressing a summit dinner in Brussels, the night before the other 27 leaders decide whether to advance the talks, May said "the clear and urgent imperative must be that the dynamic you create enables us to move forward together".

"There is increasingly a sense that we must work together to get to an outcome we can stand behind and defend to our people," she said, according to her office.

She said her speech last month in Florence, where she called for a two-year transition period and made concessions on Britain's financial settlement and EU citizens' rights, had "taken us forward" and created a "new spirit".

EU leaders have indicated they expect to decide on Friday -- at a meeting without May -- that there has not been enough progress made on the divorce issues to move onto the future trading relationship and a transition.

But May is seeking recognition of the progress made so far and agreement of "ambitious plans" that could see talks on the post-Brexit ties begin in December.

With business leaders warning of damaging uncertainty ahead of Brexit in 2019, and her Conservative party divided, May is under intense pressure to make headway.

Four former Conservative ministers urged her on Thursday to walk away without a deal if the EU continues to refuse to move the talks forward.

"It is a reality that the prime minister is working against a difficult political backdrop," a British official said.

He said she emphasised to EU leaders the importance of securing a deal that "the British people see is in the best interest of Britain. And similarly on the EU side".

May told the dinner that she made her Florence speech because she "recognised the difficulty the process was in".

"I took stock, listened to what the people in the UK were saying and what my friends and partners in Europe were saying," she said.

Brussels says there must be "sufficient progress" on Britain's financial settlement, the rights of European citizens living in Britain after Brexit, and the Irish border issue, to move talks onto trade.