BRUSSELS - British Prime Minister Theresa May said Wednesday that “now is the time” to make a Brexit deal happen, as she arrived for a summit with EU leaders hoping to unblock stalled divorce talks.

May will pitch her vision of how to save the talks on Britain’s exit from the union on March 29 to European leaders left frustrated by a dramatic breakdown on Sunday.

Hours before the summit, Germany’s Chancellor Angela Merkel said there was “still a chance” for an accord but issued a stern warning that Europe must be prepared for a no-deal Brexit.

Negotiations are at an impasse over the issue of a legal backstop to keep open the border between British Northern Ireland and the Irish Republic, an EU member.

May faces a battle to find a solution that is acceptable to both the EU and hardline Brexit supporters in her own deeply-divided party, but she insisted that a deal is achievable and that “now is the time to make it happen”.

“I believe everybody around the table wants to get a deal. By working intensively and closely we can achieve that deal,” she told reporters as she arrived for the summit.

European Council President Donald Tusk set a low bar for expectations on the eve of the summit, saying he had “no grounds for optimism” but urging May to offer new “concrete ideas on how to break the impasse”.

Lithuania’s President Dalia Grybauskaite poured cold water on hopes of major developments on Wednesday, saying “today there will be no breakthrough”.

“The main thing we would like to hear and see is strong position of UK - what really they want. Today we do not know what they want. They do not know themselves what they want,” she said.

Neither side has shown much sign of flexibility, but EU negotiator Michel Barnier is willing to add a year to the 21-month post Brexit transition period - taking it to the end of 2021, two diplomats said on condition of anonymity.

“The aim is to gain more time to negotiate the agreement on the future relationship and thus further reduce the probability of having to resort to the backstop,” one of the diplomats said.

Irish Foreign Minister Simon Coveney told the BBC that Barnier is proposing an extension, but did not say for how long.

Another diplomat warned that the idea “was not really on the table and poses a political problem for the UK.”

In any case, a longer transition would not in itself resolve the backstop issue which must be included in the withdrawal treaty and ratified before the end of March to avoid the damaging “no deal” scenario.

Even the choreography of Wednesday’s summit opening highlights British isolation.

After one-on-one meetings with Tusk, European Commission chief Jean-Claude Juncker and Irish Prime Minister Leo Varadkar, May will brief her 27 European colleagues before leaving the EU leaders to discuss Brexit over dinner without her.

Tusk has made it clear that if May and Barnier do not signal concrete progress towards a draft deal he will not call a November summit to sign it.

Instead, the matter could either be pushed back to December or - more dramatically - the EU could use the November weekend to meet on preparations for a “no-deal” Brexit.

Previously, both sides had agreed that Britain crashing out of the Union on March 29 next year with neither a divorce agreement nor a road-map to future ties would be an economic and diplomatic disaster.

“There are still several weeks of space left, according to what the British are telling us, and they are the ones with calendar problems,” said a senior EU diplomat. But with the row over the Irish border, fears of a debacle are mounting.

A senior European official said a speech by May in the House of Commons had only underscored for Barnier the uphill struggle he faces to get an agreement.

To solve the Irish question, Britain has proposed staying aligned to the EU’s customs rules until a wider trade deal can be signed that avoids the need for any frontier checks.

But her own eurosceptic Conservative MPs are demanding this “backstop” arrangement be time-limited, something the EU will not accept.

May said the EU was also insisting on its own “backstop” in case the London proposal did not work, which would see Northern Ireland alone stay aligned to the customs union and single market.

She says this would threaten the integrity of the United Kingdom - and it is strongly opposed by her Northern Irish allies from the Democratic Unionist Party (DUP).

Europe’s biggest auto firms on Wednesday warned that a no-deal Brexit would “threaten their very business model” by disrupting component distribution.