Britain's government redoubled its efforts Thursday to find common ground with the opposition as German Chancellor Angela Merkel said she still hoped a chaotic Brexit could be avoided next week.
Downing Street hailed a second consecutive day of cross-party negotiations between senior ministers and their counterparts from the Labour main opposition as "detailed and productive".
But the talks broke up Thursday after nearly five hours without signs of a breakthrough to ease months of political crisis over Britain's departure from the European Union.
Both sides said they planned to reconvene Friday.
Prime Minister Theresa May is racing against the clock in a desperate search for votes that could push through, on the fourth attempt, the divorce deal she struck with the other 27 EU leaders.
Britain's latest Brexit deadline is April 12 and resistance to her plan remains passionately strong.
Meanwhile increasingly weary EU leaders -- tired of the political drama in London and eager to focus on Europe's own problems -- want to see a deal passed or a viable new plan presented ahead of a summit Wednesday in Brussels.
Flanked by Irish Prime Minister Leo Varadkar during a visit to Dublin, Merkel welcomed the discussions in London as increasing the chance that May would have "something to table to us".
"I will do everything in order to prevent a no-deal Brexit," Merkel said. "But we have to do this together with Britain.
"Where there's a will, there's a way," she added.
'Very little time left'
European leaders must decide whether to grant May's request to push back Brexit until May 22 -- the day before member states begin electing a new European Parliament.
One alternative is to force May to accept a much longer extension that could give Britain time to rethink Brexit and possibly reverse its decision to leave.
Another is to let Britain go without a deal on April 12 in the hope that the economic disruption is short-lived and worth the price of eliminating long-term Brexit uncertainties.
Neither Merkel nor Varadkar would be drawn on the extension.
"There is very little time left and we have to prepare ourseleves for all outcomes," the Irish premier said.
May dramatically ended her courtship of her own Conservative Party's holdouts and resistant Northern Irish allies by turning to the main opposition Labour Party this week.
But her decision to hear out their veteran leftist leader Jeremy Corbyn's demands for a closer post-Brexit alliance with the bloc that includes membership of its customs union has enraged right-wing Conservatives and seen two junior ministers resign.
One senior minister said May had no other choice.
"It's very simple: there's nowhere else to go," the unnamed cabinet minister told the news website Politico.
Pro-European members of May's team insisted it was time to compromise on long-standing beliefs for the benefit of a safe resolution of Britain's biggest crisis in decades.
"There is going to be pain on both sides," finance minister Philip Hammond told ITV television.
'British interests first'
Yet even some members of May's own cabinet publicly questioned the wisdom of putting Brexit's fate in the hands of the Conservative Party's rivals for power.
Health Secretary Matt Hancock -- tipped as one of several potential successors to May -- told BBC radio that Corbyn was "a Marxist who never once in his political life put British interests first".
May and Corbyn have competing visions of Britain's place in Europe and neither has shown much willingness to compromise in the past.
The Times newspaper quoted an unnamed government source as saying that May's office thought it more likely than not that the negotiations would fail.
May has resisted the customs union idea because it bars Britain from striking its own independent trade agreements with nations such as China and the United States.
And Corbyn is under pressure from Labour's pro-EU wing to push for a second referendum that would pit May's final agreement against the option of staying in the bloc.
Corbyn has shied away from backing another vote due in part to his own sceptical view of Brussels.